You could use a combination of functions:
Left(string, n) can be used to substring the n left-most characters
Mid(string, m[, n]) can be used to substring from the m-th character for a length of n (or until the end)
Right(string, n) can be used to substring the n right-most characters
Instr(1,string1, string2, vbTextCompare) can be used to determine the value of n and m in the above functions.
So for example InStr(1, NameField, ",", vbTextCompare) would give you the position of the comma in your name field, so to get everything to the left of that you could use:
Left(NameField, InStr(1, NameField, ",", vbTextCompare) -1)
Note the "-1" becuase you need everything up to but not including the comma.
You can use such syntax in update queries to populate your new name fields.
Helpful?