Try out the the MID function. It works like this, the first parameter is the string you want to parse. The second is the start postion for "cutting", the third paramter is how many characters you want to "cut". So ...
mystr = MID("a@b@c@d@e",3,3)
Wscript.Echo mystr
mystr = MID("a@b@c@d@e",7,3)
Wscript.Echo mystr
Should return "b@c" and "d@e" respectively