1. Performance person. yes --> if possible sell entire system to recoup cost, upgrade to LGA1155 core i3 2100 if no need to pay Windows License again. Even better to go for i5-quad.
2. Value people. any used C2Q quad below USD90. Use remaining to buy RAM where sensible. Create 4GB RAM-Disk, put frequently used files/temp storage on RAM-Disk. Why only 4GB, mostly free upto 4GB(I think). for more need to purchase license for Windows RAM-Disk software
suggestion only. verify with forum members about your actual configuration and software usage scenario.