PC build for 450€/3500kr Norway

Oh, you use HTML for the posts here.

 Anyway, hello.

I have just moved to Oslo so the location for websites or stuff like that should be Norway or deliverable to Norway.

I'm planning on building myself a PC for about 450€, which is my current maximum budget, that I'll probably have to convert into the local currency, Norwegian Krones, first. 

I will use it for internet navigation, videos, a very little bit of blender (last priority on my list) and some light gaming. Currently I have Portal 2 and Fallout New Vegas, ideally I'd like to play them on max settings with 60+ fps, but since I'm not stupid and I know that 450€ isn't exactly an amazing budget I'd be happy to play them with constant 30+ on medium or so.

I need to buy a monitor, a mouse and a keyboard, too.

Monitor: at least 1360x768, with DVI or VGA (I want to be able to connect my XBOX)

Mouse: just a usable mouse, possibly cheap but not microscopic

Keyboard: pretty much everything goes, though I'd like to hear what you'd think about me getting a DVORAK (I'm open to change)

Case possibly with noise isolation, but I'm on budget so prioritise other things first.

Possibly a DVD drive, I have an external one eventually but  would be nice to have it

CPU and GPU: well, I'm kinda lost here ^^ that's why I'm asking you guys

HDD: no need for an SSD, minimum of 500GB, maybe a bit more (I should be happy with 1TB)

Oh yeah, I forgot I need an audio system: You can pretty much recommend me anything. I've been using crappy 10€ cinese speakers till now on the family desktop, and even worse on this netbook (which by the way is falling apart and will be replaced by this)

Motherboard: no clue, sorry. Need wifi though (can't reach wire :/)

PSU: whatever works

RAM: 4GB, if there's some money left add as you like

 

This will be my first PC build, so thanks for the help! :D

P.S. there might be a chance that I'll be able to add 50-100€ (400-800kr), so if possible can you give me tips on what to invest more in case this little miracle happens?

 

EDIT: Dammit I knew I forgot something haha.

The OS.

I would use Ubuntu, but I'd like to play games, too, so would you happen to know where to buy windows 7?

Or, even better, is there a way to copy windows 7 from one hard disk to an external hard drive and then install it on the new PC?

http://www.newegg.com/Product/Product.aspx?Item=N82E16883229285 its a budget setup a bit under your price but the rest of the budget can go towards a screen (good luck !)