From what i could get from the guide and Cpu-Z, this is the information you guys need:

Motherboard -
Manufac: ASUSTeK Computer Inc
Model: K8V-X SE

Graphics Card -
Name: Nvidia GeForce 6200

Memory -
Type: DDR
Size: 1024 MB
Channel #: Single

Cpu -
Name: AMD Athlon 64 3400+
Core Speed: 2203.0 Mhz

PSU (Planning to upgrade) -
Manufac: Mercury
+12V: 15A
Watts: 300

Games i play are in example of Viva Pinata, Sims 2 (W/ all Expansions), Oblivion (W/ all Expansions), Civ 4 (W/ all Expansions). I am intrested in upcoming games Spore, Starcraft 2 and Assasains Creed. Also, for note, im using an old monitor, so im playing and using most things in 1024x768.

Im in England: I have roughly the money to make around a £50 purchase. If i save longer, which is harder, i could probally make it to around £80. Saving considerbly longer (around 2 months), id be able to make £100.

The reason i ask for advice is because im Poor - literally. Im below the poverty line. I make just enough to buy food, electric and pay rent. I dont even have heating, or a Tv.

Also while here, anybody have any upgrade suggestions for the future on things to make this run faster, and in general function so it can run a heavier workload?

This video card along with this PSU oughta help you out. Sorry, but you can't get a PSU and video card better than your current specs for under £50. These are the best I could find. As for future upgrades, you'd need a complete revamp since your motherboard's outdated and processors are very difficult to find for it, plus there are no dual-core CPUs for it either. so you'd basically need a new PC or to get a motherboard like the Asrock 4CoreDual or the Asrock 775DUAL which support all the LGA775 Intel processors, PCI-E and AGP cards and DDR and DDR2 RAM and move all your existing parts to it, while getting a new CPU like the new Intel Dual-Core E2140 since your current one won't fit in it. In any case, good luck and let us know how it goes.

You got 2 options - you cant get a much better GC without the need for a better PSU that'll direct pump juice to the GC - you could get a budget 500W and ATi Radeon X1550 for £70 (cclonline/ebuyer) or a X1650 /PRO will cost upto £60 on its own. The downside to this would be your PSU - would it bring in the preformance youd need from a demanding GC?

Alternatively, you could buy a new PC - 775 socket and budget Core Duo chip (>1.6GHz) for £300 minus a GC - but a PCI-e X1650 can be purchased for an extra £30.

I'd say:
Ati Radeon 2400 Pro - £29.99
Antec EarthWatts 380W PSU - £29.99

*edit: I'd also suggest getting an extra GB of ram but since it's DDR-I it's quite steep (around £31 for 1GB)*