Not sure what you are looking for exactly but maybe this will help you.
Dim RandomClass As New Random()
Dim RandomNumber As Integer
Dim strStringPart As String = Month(Now).ToString & Year(Now).ToString
Dim NewRandomNumber As Integer
RandomNumber = RandomClass.Next(1000, 9999)
NewRandomNumber = Int32.Parse(strStringPart & RandomNumber)
'NewRandomNumber contains 220135765 which is month, 4 digit year, and random number between 1000 and 9999
hope that helps or gets you in the right direction.