I don't speak Spanish, but the site seems very pleasant. Except gray backgrounds which I don't like in way it is used on this site (for me it looks like unfinished or very old site.)
For your content area, I think the colors are to bright, I would use the same colors but with a paler/lighter tone. Also, the highlight could be changed to yellow instead of bright blue.
I don't speak spanish, but the images for the auctions are all different sizes, maybe try setting a fixed image size, and a mouse-over for the full image?
Hmmm...I think there's too many colours overall. Perhaps simplify the colour scheme in the 'descatodos' (sorry I don't speak Spanish) section as it is this section that seems to mismatch with the rest of the colour scheme.
to the main poster.... is the site still up and running? I just went to it.. and it doesnt look like an auction site it looks like a webpage with links/adds to other sites...