Thinking of upgrading need some advice plz

[=GAMMO=]

Right this is what ive got..

Amd 3500 Newcastle skt 939
ThermalRight XP-120 cpu cooler
Abit Av8 3rd eye Mobo
Galaxy 6800gt 256mb AGP
Tagen 480w PSU
Western Digital Caviar SE16 250GB
Western Digital Raptor 74GB
Crucial Ballistix PC4000 2x512mb

Now just thinking of upgrading, but only thinking because this will all depend on what the upgrade will cost and what will need upgrading. Been away from tinkering with comps for a while so stick with me. Looking at the Conroe from a quick browse looks like its the new big thing but what am i going to need to change to swap over from my current AMD setup? Also, what prices could i expect to sell my not needed parts for? One last thing i'd like to keep as much of my current system to keep costs down if at all possible?

Thanks in advance for any advice peeps

=GAMMO=

 

[semi-pro waster]

To upgrade to Conroe you would need a new motherboard, new CPU(kind of obvious this one ) and new Ram as well as a new graphics card, the rest you could re-use. Something like this may be suitable although you can maybe do it a shade cheaper, I don't think you can re-use your existing CPU cooler.

CP-135-IN Intel Core 2 DUO E6300 "LGA775 Allendale" 1.86GHz (1066FSB) - OEM (CP-135-IN) 1
£114.95 £114.95
HS-020-ZA Zalman CNPS9500-AT Aero Flower (Socket 775) CPU Cooler (HS-020-ZA) 1
£28.95 £28.95
MY-095-CS Corsair 2GB DDR2 XMS2-5400 TwinX (2x1GB) (MY-095-CS) 1
£111.95 £111.95
MB-003-AK Asrock ConroeXFire-eSATA2 (Socket 775) PCI-Express DDR2 Motherboard (MB-003-AK) 1
£53.95 £53.95
GX-044-CO Connect3D ATI Radeon X1800 XT 256MB GDDR3 AVIVO TV-Out/Dual DVI (PCI-Express) - Retail (GX-044-CO) 1
£126.95 £126.95
Subtotal £436.75
VAT £76.44
Total £513.19

As for pricing your old parts I'm not too sure, maybe something along these lines as a very rough guess:
3500 Newcastle - £40
Abit motherboard - £20-30
Galaxy 6800gt - £80-90
Crucial Ballistix - £50-60