You need to set the multiplier for your ram lower and then increase the fsb.
But if your not planning on overclocking and want a new chip, don't get that 925. 2.8ghz These days ... Either get an athlon II 640 or an phenom II 955.
Also your saying your chip isn't good because it has an old architecture ... phenom II has the exact same architecture, athlon II just doesn't have the L3 cache.
The Phenom 925 is the same model processor as the 955 just with a lower clock which is easily fixed by our favorite method.