Theirs no way putting a frist gen phenom will last.It's a wasteful upgrade path.Your gonna have to go for AM3.
This should work for your $150 budget.
ASRock AM2/AM2+/AM3 Mobo $53 + $7 Shippinghttp://www.newegg.com/Product/Product.aspx?Item=N82E16813157226
Phenom ii x4 955 @ 3.2ghz $115+ Free Shipping
It should be around $170 after taxes and shipping and I realie thats a little over your budget but it's well worth it.With this new CPU should get 60+fps.