It should be good, my friend has a e5200, the one belows urs and i think a 7750 wouldnt bottleneck with it so maybe im guessings its 2gb of ram, most modern games recommend 4gb, im not sure if this would cause low gpu usage.
I bet your cpu runs 100 % to try feeding your gpu - so changing to a faster cpu should give better gpu usage . You should be able to find a Core 2 Dou like E6600 (2.4 Ghz) or E6700 (2.66 Ghz) or a Quad-core like QX6600 (2.4 Ghz) or qx6700 (2.66 Ghz) and allso change to Win 7 64 bit would help
oh i just now tested assasin creed brother hood and found 90 % gou usage
i think that games that need high cpu usage slow my gpu cuz the cou is fully taken and
cant handle my gpu (brother hood is running smoth on almost maxed out setting except for shadows and post effects)