Just go pokesav it in. But you might as well just directly edit the pokemon's level. And you might as well just give it all of the moves that you want it to have... And I could keep going...
Use a save converter. Luckily, my Cyclo already saves it in the native format used by pokesav. You'll have to reconvert it back to its original format when you're done editing.
Here are some ... not many, and some aren't very useful but the main ones are here. http://cheats.gbatemp.net/Temp/ Hope it helps.