E-350 and Sempron 145 are similar in CPU perf but E350 is much smaller and low power and better gfx - http://www.cpubenchmark.net/midlow_range_cpus.html
Suggest a mini ITX AMD E350 cpu mobo combo for ~4.5k & sell off your ddr2 & purchase ddr3 with the money made. Abt as power ful as your current setup...
Where are you from? Check my thread here - http://www.techenclave.com/community/threads/core2quad-2x2gb-ddr2-2gb-laptop-ddr3-1333-chieftec-atx-cabby-2-ide-dvdrws-dead-g41-775-mobo.154143/
Selling my old desktop parts as the mobo died & i decided to go ivy bridge ITX; currently not open to shipping & looking for local Mumbai deals only. Do post if youre interested out of Mumbai & i will consider on case by case basis especially for laptop RAM and the CPU. Here goes...