Well, to get that thing you have two solutions:
1-Downloading it. Both you and me will be (you by doing it, me by telling you to do that) probably banned because of getting copyrighted material of the Internet; but sometimes people have to take some risks...
2-Dumping the file. More accepted among users but it´s almost impossible since almost nobody has a GBA in these days.
Apart from that: Do you mind to put your PC specs here? Multiplayer mode needs a lot of processing power...
1-Downloading it. Both you and me will be (you by doing it, me by telling you to do that) probably banned because of getting copyrighted material of the Internet; but sometimes people have to take some risks...
2-Dumping the file. More accepted among users but it´s almost impossible since almost nobody has a GBA in these days.
Apart from that: Do you mind to put your PC specs here? Multiplayer mode needs a lot of processing power...