Upgrading my PC, need advice

Hey Tek folks, first time posting here but I've been watching the stuff on YouTube for a long time so I figured I'd ask you guys since you probably know more than I do.

I'm upgrading my desktop because some of the parts in it are pretty weak, I'm probably not looking for a complete overhaul but it's not out of the question. I'm from Denmark so preferably I'd buy from danish stores - we use DKr (Danish krone/crown). The games I'd be using it for are Civ 5, LoL, DotA 2 mainly. I don't play shooters really, but I do have a copy of Deus Ex: HR that I'd like to play. Other than this, I've been levelling to 50 in SWTOR on my laptop and would like to play it on my desktop as well. I don't use my computer for rendering anything at all, I've never overclocked my PC (but I could do it if there's good money to be saved), and I don't use water cooling (but I have a friend who could help me get this set up later if I wanted).

Here's my current specs:

Processor: i5 750 @ 2.66 GHz (quad core)

Geforce 9500GT, 512 MB (i seem to recall this is the one, dxdiag says 1837 MB total memory but I'm guessing this isn't all dedicated or something...)

Memory: 2x2GB Kingston 1333 MHz (this one i'm in doubt about, can't really remember but i googl'd the package they came in and got this http://www.kingston.com/us/memory/search/?dispartid=kvr1333d3n9/2g - which looks right)

Motherboard: ASRock P55 Pro

PSU: Linkworld Diamond 800-Watt

Windows 7 32-bit Professional

 

I'm mainly looking into a new graphics card (the 9500GT barely runs anything it seems) - my friend recommended I take a look at these two (click "Specifikationer" for their specs):

http://www.edbpriser.dk/grafikkort/msi-n760-tf-2gd5-oc-2-gb-id-7445055.aspx

Looking at this one, is this just a GTX 760? Anything special about it?

http://www.edbpriser.dk/grafikkort/xfx-radeon-hd-7870-2-gb-id-6712803.aspx

This is obviously a HD 7870, not much doubt there.

Right now I'm leaning more towards the 760 because I've used nVidia all my life, and it also looks like it does really well in benchmarks - but the other card is 500 DKr cheaper so it's hard to say which one is the better deal. One thing that I don't quite understand is PCI Express 2.0 and 3.0 - My mother board apparently uses 2.0, but these cards are 3.0 - does this mean I need a motherboard upgrade?

 

Other than this, I need to upgrade to 64 bit windows - hopefully windows 7 because i don't like 8. I have a friend who should be able to get me Windows 7 for cheap, so I don't really need help. But since I'm getting 64 bit, I want some more RAM. I tried to play SWTOR on my desktop and my RAM usage just capped and it was awful.  I'm looking into getting this package: 

http://www.edbpriser.dk/ram/kingston-hyperx-blu-2-x-8-gb-id-7077713.aspx

- but i'm not sure that this is really what I need. I was told that I can run this along side my other 4 GB RAM but that I would have to lower the clock speed on the new stuff. And do I really need 20 GBs of RAM? (probably not). I don't know much about RAM, all I know is that I use all of it pretty easily.

Other than this, I don't really want to make any upgrades. Maybe an SSD - but they seem expensive and I don't see what I need it for. I could be persuaded to do a full upgrade, but you would have to show me some very convincing prices or arguments regarding performance. I'd be willing to spend DKr 2800 on a graphics card/RAM upgrade (but hopefully somewhat lower since I don't really feel like spending 1000 on RAM...), and 4000 on a totally new build (I have harddrives, optical disk drive, mouse/keyboard, speakers and monitors)

Hopefully you can help me out here :)

you need a 64bit os first of all. any upgrades would be pointless without that.

Yup, I have no idea why you're running 32-bit windows...

That RAM looks nice.  I have the 2x4GB, which works for gaming.  I never max out.  I've only gone up to 6.5GB of usage(Integrated HD 4000, too).

The GTX 760 should be faster than the 7870.  Also I don't really like XFX cards, but that's just personal preference.