Its not too bad, maybe consider a fixed width so users dont have to take in too much infomation at once? around 600 px.. maybe 650..
After that you then have plenty of room for some drop shadows..
and then a soft gradient background could help.. make it about 1000px high and 1 px wide.. and then tile it..
Maybe a different border colour.. or none.. then check out http://www.html.it/articoli/nifty/index.html
for making round corners without graphics..
and finally a nice tile-ling blue gradiant for the top menu bar..
These will give the site a new look.. plus wont slow it down too much..