I've been working on hacking a Pokemon Fire Red, using only the program called Advance Text. Very eager to finish it, but I was wondering if there is anyway to put my modified Pokemon ROM onto a GBA cartridge, to be able to be played on a GBA?

You'll need to buy a GBA Flash Card.  If you want to play any of the GBA Pokémon Games, make sure you buy one which has a Clock Battery in.