Yeah, definitely what ive learnt
In the long run you spend more time and money on upgrading stuff you should have got in the first place and before you know it, it's end of line and prices rocket...then you spend your nights on flea bay endlessly watching auctions!

In all serioiusness, OP try to scrounge a bit more together, or perhaps look at AM3 Athlon II Tri Core paired with a GTX460. You'll at least have some sort of upgrade path in the future with Phenom II Hex Core or if you get a AM3+ board, Bulldozer.
Below is a slightly cheaper AMD option.
OcUK GeForce GTX 460 768MB GDDR5 PCI-Express Graphics Card - OEM OcUK GeForce GTX 460 768MB GDDR5 PCI-Express Graphics Card - OEM £85.99
(£71.66) £85.99
(£71.66)
AMD Athlon II X3 Tri Core 450 3.20GHz (Socket AM3) - Retail AMD Athlon II X3 Tri Core 450 3.20GHz (Socket AM3) - Retail £59.99
(£49.99) £59.99
(£49.99)
MSI 880GMS-E35 AMD 880G (Socket AM3) DDR3 Motherboard MSI 880GMS-E35 AMD 880G (Socket AM3) DDR3 Motherboard £51.98
(£43.32) £51.98
(£43.32)
BeQuiet Pure Power L7 530W '80 Plus' Power Supply BeQuiet Pure Power L7 530W '80 Plus' Power Supply £45.98
(£38.32) £45.98
(£38.32)
Cooler Master Elite 335U Case - Black Cooler Master Elite 335U Case - Black £31.99
(£26.66) £31.99
(£26.66)
Samsung SpinPoint F3 500GB SATA-II 16MB Cache - OEM (HD502HJ) Samsung SpinPoint F3 500GB SATA-II 16MB Cache - OEM (HD502HJ) £30.98
(£25.82) £30.98
(£25.82)
Kingston HyperX Blu 4GB (2x2GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (KHX1600C9AD3B1K2/4G) Kingston HyperX Blu 4GB (2x2GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (KHX1600C9AD3B1K2/4G) £26.99
(£22.49) £26.99
(£22.49)
Samsung SH-S222AB/BEBE 22x DVD±RW SATA ReWriter (Black) - OEM Samsung SH-S222AB/BEBE 22x DVD±RW SATA ReWriter (Black) - OEM £17.99
(£14.99) £17.99
(£14.99)
Sub Total : £293.25
Shipping cost assumes delivery to UK Mainland with:
DPD Next Day Parcel
(This can be changed during checkout) Shipping : £10.50
VAT is being charged at 20.00% VAT : £60.75
Total : £364.50
Won't be as quick as i3 2100 but motherboard will take Bulldozer CPU's in the future. If you can get together enough for i3 this'd definatley be the better option.