Thank you all for so gr8 replies.
About the ram: I do need a new motherboard for that, because for sum strange reasons I do not understand my moterboard can't support more than 2GB of ram 
or else I would have around 5 GB of ram now.
About the processor: I would overclock my current 1 but I'm scared that I will initiate a core meltdown in my computer and i don't know how. Also I don't have the money to buy a quad core right now. I'm saving 90% of it for my drivers license
About graphics card: I know its not the best card now, but it should at least be able to run Crysis on medium or maybe high.
EDIT: I didn't read too closely. If you're "saving up" for a driver's license I'm going to assume that you live with your parents and that the computer you are using is theirs. I don't think they'd be too happy if they found out you were overclocking and potentially voiding warranties... don't do the following unless it is your own hardware and you're willing to accept the small risk that you might screw something up.
A quick FAQ on OverclockingIs overclocking unsafe? Will I cause a core meltdown? Overclocking is only dangerous if you're not careful. If the first thing you do is crank up your Core Voltage to its maximum you'll burn out your processor, motherboard, or RAM. Overclocking can be quite safe if you approach it slowly and gradually. If you overclock in small steps you will definitely notice system instability long before any damage occurs.
What about heat? Overclocking does cause your processor to make a lot more heat. I would not advise letting your CPU go above 70°C for prolonged periods. If you get this hot, buy a better heatsink or hold back on the overclock.
What does FSB, Multiplier, and vCore mean? These are the three main things you'll be tweaking when you overclock. Your overall processor frequency (2.8 GHz or 2800MHz) is equal to the Front Side Bus (FSB) speed times the Multiplier. In your case, the FSB is 800Mhz and the Multi is 3.5. 800 times 3.5 is 2800MHz. vCore is the voltage going through your processor, and ranges from about 1.2V to 1.7V.
- The Multiplier is usually
locked, which means you can't increase it.
- The FSB can be changed easily as long as your motherboard lets you.
- Increasing vCore doesn't directly increase speed, but it can make your processor more stable.
So how do I DO it?You'll need to get into your motherboard's BIOS. This usually means holding down the Del key while your computer boots up. Once in the BIOS you'll have to find the page that controls frequencies and voltages. Not all BIOSes have this.
1) Find FSB speed and increase it by 25MHz or so. Save and exit the BIOS settings.
2) Boot into Windows and use a program like Prime95 or Orthos to "test" your overclock. Let the test run for at least 10 minutes. Keep an eye on your temperatures, if they go too high decrease your FSB and stop.
3) If there are no errors reported by the test, repeat Steps 1 and 2. Don't continue to Step 4 until you get an error.
4) The error means the overclock is unstable. You can either
a) reduce the overclock so that the errors go away and stop here.
b) increase your vCore a bit and see if you regain stability. Once you gain stability you can go back to increasing FSB. Don't go past 1.45V unless you have very good cooling.
5) Once you have a speed that you like that appears stable, run the test for a lot longer... at least a couple hours. If there are no errors you have a stable overclock and can go about your business.
What do I do if I get to a point where my computer won't even boot? You'll have to clear your CMOS. Google it before you start
There are other tweaks you can do to get even better overclocks, but that's a little more complicated.
The above was provided as a very quick guide to newbie OC. I take no responsibility if you manage to screw things up.
