Use vlan to isolate a computer

First off, let me apologize for my inexperience in the networking world.  I am part of a small company and I AM are IT guy and I am learning as I go.

Here is my situation:
I have 5 static IP address asssigned to me by my internet provider.  Lets say they are 67.67.140.201 - 205.
I currently have one ethernet cable entering into the building that supplies my internet connection.  That cable is connected into port 1 of my router which is set up as its very own vlan (vlan 2).  The rest of the ports on my router are set up on a seperate vlan (vlan 1).  I use NAT to direct traffic from the incoming (vlan 2) feed to the rest of the network connected on vlan2.

I have a need to allow someone to access a computer on my network using one of the static IPs (67.67.140.203) that have been assigned to me by my internet provider.  It seems to me that setting up a new vlan for that computer to connect to and then forward the incoming traffic from the 67.67.140.203 IP address to the new vlan would be a reasonable answer to this issue.

Does this seem like a good way to do this?  And if so, how exactly do I go about it.

My initial thought is to assign the incoming IP (67.67.140.203) to the vlan, assign a port on the router to that vlan and than connect the computer to that port.  My only question is; what do I set the computers IP, gateway, etc to?  Does this sound right?

If there is a cleaner, better way to do this, please let me know.

Thanks for any help.
Rick