Nope. Your bios has to support the software overclocking in which your bios doesn't. You're stuck with that speed because Gateway is lame like that. You can buy a cheap AM2+ motherboard for like $30-40 and then you'll be able to overclock, but you might as well upgrade the cpu too if you're gonna upgrade the motherboard, you might as well upgrade the AM3 cpu.
Sorry to say, but sucks for you~ hehehe. Hey, I at least answered your question.