Hi Bojan,
Welcome to CF! You look like you've more or less got all the building blocks in place, but just need to clean things up a little. Here are a few examples:
All in all it's quite basic, so you can do much wrong. What you want to make sure of is that your typography and container margins are all fixed up as I see that as your biggest disadvantage for now. The red would then be the next biggest issue (it's fine that the client likes it, but there is more than one way to rome ;) ).
Good luck with the site!
Cheers
Noel
Hi, Okay first of all you are on the right path here, and the only thing that I like is the top nav links with the gray gradient, but the rest need more attention and lots of adjustments!
I will use some notes!
But let me give some example that might inspire you and take this design to a new level, to Web 2.0 level ;)
http://themeforest.net/item/business-template-for-company-profile/fullscreenpreview/83454

I like the gray gradient it fits well here, but the zones around it needs more attention!
You Nav menu gradient is too simple, your top padding is bigger then the bottom padding, and you can put there a border:1px solid #920000; and -moz-border-radius:5px; -webkit-border-radius:5px;
So...what's up with this zone? This red background need to go away!!!! Replace it with a red gradient or gray gradient mixed with a 20px red line I'd say...
Your login box is to dark, need more attention! Don't make the background that dark...lighten up a little bit!
Expand the height Footer a little bit so you can arrange the information much more easy!

Replace this red background with a red gradient or a gray gradient mixed up with a red line!!
Ok, the client likes red which is fine - but I would try and use it as more of an accompanying colour (with some soft tones, or mono or earthy even) rather than a main colour ..
On further review - this is actually hurting my eyes the more I look at it .. sorry!