It looks like the best bet is probably the AMD Phenom II X4 945 Deneb 3.0GHz
here's a link to it on newegg:http://www.newegg.com/Product/Product.aspx?Item=N82E16819103809
It has the same 95W TDP of your current CPU, and with a BIOS update your motherboard in the dx4200 should work with am3 CPU's.
I have a dx4300 I was going to do this with, but bought a x2 550 BE at the time because it was a lot cheaper, but now the x4's are only 30 bux more.
Keep in mind you have a maximum of 95W CPU support for this board, don't go looking at the 125 W phenom II's.[/quotemsg
The Phenom x4 9100e is a am2+ socket, with a tdp of 65 w, the Phenom x4 9450 has a b3 step at 2.2GHz 1.8 GHz ht, which is a little faster, any processor above this one has a higher tdp, like the 945. So as far as I can tell the 945 am3 chip will not fit, and will overheat, it that correct? thank you.