Can I upgrade to Athlon XP

I have a PC with an AMD Athlon A 1.3GHz processor on an ASUS motherboard with the AMD Irongate4 Chipset. I would like to upgrade but am not sure whether my motherboard can handle an Athlon XP+ with the current architecture. If yes, what is the max speed, if no can I go up to the Athlon A 1.4GHz (266FSB) or will I have to just change my motherboard completely.