Regex Questions

I'm currently using the code below to extract data.  I want to change the code to perform the same function except I need to exact data based on and IP address or a domain name. For example 61.1.1.1 or yahoo.com.  I don't need to have the application do both.  I just want to replace/modify this line when I need to change the search criteria.

        Dim re As New Regex("^.*?Not\sin\sDatabase.*?$", RegexOptions.Multiline)

'working code below

Imports System.Text.RegularExpressions
Imports System.IO

        Dim re As New Regex("^.*?Not\sin\sDatabase.*?$", RegexOptions.Multiline)
        Dim sr As New StreamReader("C:\resource\input.txt")
        Dim input As String = sr.ReadToEnd()
        sr.Close()
        Dim mc As MatchCollection
        Dim sw As New StreamWriter("C:\resource\results.txt")

        mc = re.Matches(input)
        For Each m As Match In mc
            sw.Write(m.Value)
        Next
        sw.Close()

Thank you in advance for your time and expertise,
Gr8life