Brute force attack RDP Eventid 4625 help

I have since days ago this kind of illegal auditing on my eventids on my windows 2008 server:

Log Name:      Security
Source:        Microsoft-Windows-Security-Auditing
Date:          30/09/2012 10:44:09 a.m.
Event ID:      4625
Task Category: Logon
Level:         Information
Keywords:      Audit Failure
User:          N/A
Computer:      mycomputer
Description:
An account failed to log on.

Subject:
      Security ID:            SYSTEM
      Account Name:            mycomputer$
      Account Domain:            WORKGROUP
      Logon ID:            0x3e7

Logon Type:                  10

Account For Which Logon Failed:
      Security ID:            NULL SID
      Account Name:            Administrator
      Account Domain:            mycomputer

Failure Information:
      Failure Reason:            Unknown user name or bad password.
      Status:                  0xc000006d
      Sub Status:            0xc000006a

Process Information:
      Caller Process ID:      0x2d40
      Caller Process Name:      C:\Windows\System32\winlogon.exe

Network Information:
      Workstation Name:      mycomputer
      Source Network Address:      68.205.23.216
      Source Port:            2098

Detailed Authentication Information:
      Logon Process:            User32
      Authentication Package:      Negotiate
      Transited Services:      -
      Package Name (NTLM only):      -
      Key Length:            0

This event is generated when a logon request fails. It is generated on the computer where access was attempted.

The Subject fields indicate the account on the local system which requested the logon. This is most commonly a service such as the Server service, or a local process such as Winlogon.exe or Services.exe.

The Logon Type field indicates the kind of logon that was requested. The most common types are 2 (interactive) and 3 (network).

The Process Information fields indicate which account and process on the system requested the logon.

The Network Information fields indicate where a remote logon request originated. Workstation name is not always available and may be left blank in some cases.

The authentication information fields provide detailed information about this specific logon request.
      - Transited services indicate which intermediate services have participated in this logon request.
      - Package name indicates which sub-protocol was used among the NTLM protocols.
      - Key length indicates the length of the generated session key. This will be 0 if no session key was requested.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-a5ba-3e3b0328c30d}" />
    <EventID>4625</EventID>
    <Version>0</Version>
    <Level>0</Level>
    <Task>12544</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8010000000000000</Keywords>
    <TimeCreated SystemTime="2012-09-30T15:44:09.477Z" />
    <EventRecordID>4297067</EventRecordID>
    <Correlation />
    <Execution ProcessID="716" ThreadID="3656" />
    <Channel>Security</Channel>
    <Computer>mycomputer</Computer>
    <Security />
  </System>
  <EventData>
    <Data Name="SubjectUserSid">S-1-5-18</Data>
    <Data Name="SubjectUserName">mycomputer$</Data>
    <Data Name="SubjectDomainName">WORKGROUP</Data>
    <Data Name="SubjectLogonId">0x3e7</Data>
    <Data Name="TargetUserSid">S-1-0-0</Data>
    <Data Name="TargetUserName">Administrator</Data>
    <Data Name="TargetDomainName">mycomputer</Data>
    <Data Name="Status">0xc000006d</Data>
    <Data Name="FailureReason">%%2313</Data>
    <Data Name="SubStatus">0xc000006a</Data>
    <Data Name="LogonType">10</Data>
    <Data Name="LogonProcessName">User32 </Data>
    <Data Name="AuthenticationPackageName">Negotiate</Data>
    <Data Name="WorkstationName">mycomputer</Data>
    <Data Name="TransmittedServices">-</Data>
    <Data Name="LmPackageName">-</Data>
    <Data Name="KeyLength">0</Data>
    <Data Name="ProcessId">0x2d40</Data>
    <Data Name="ProcessName">C:\Windows\System32\winlogon.exe</Data>
    <Data Name="IpAddress">68.205.23.216</Data>
    <Data Name="IpPort">2098</Data>
  </EventData>
</Event>

   Now I know is someone trying to brute force enter to my windows 2008 now how the IP of the user is dynamic or in other words in all way each time I block the IP of the attacker, this attacker create a new IP from any part of the world in an endless situation I suppes that attacker has an script to create new IP and continue the attack. Now I found on Google this script and works excellent:

https://github.com/EvanAnderson/ts_block

   I configured that script to block the IP after 2 failed attempts and to remove the IPs after 1 month from firewall and does the Job fine like I said.
   Now the issue is that the attacker still hammering the system the ts_block script does the job very well block the IPs but the problem is all day is a game of the attacker creating new IPs now I saw this too:

http://www.2x.com/securerdp/

   And that software can block the access avoiding to the attacker enter to a log in screen but the sad history is that not work in windows 2008. Exist a similar software for windows 2008 where I can limit access via computer name or mac address I mean give permission of some computer names and or via macid like SECURERDP for windows 2003?
   Any other suggestion too for increase security or software to use?
Thank you