Lets see. CPU upgrade options first.
Intel Celeron processor 430
Intel Celeron Processor 420 (1.6 GHz, 800 FSB)
Wolfdale Dual Core E7300, 2.66, 3MB, 65W, M0
Wolfdale Dual Core E8190, 2.66G, 6MB, 1333FSB, 65Watt, C0
Wolfdale Dual Core E8200, 2.66G, 6MB, 1333FSB, 65W, C0
Wolfdale Dual Core E8300, 2.83G, 6MB, 1333FSB, 65W, C0
Wolfdale Dual Core E8400, 3.00G, 6MB, 1333FSB, 65W, C0
Wolfdale Dual Core E8400, 3.00G, 6MB, 1333FSB, 65W, E0
Wolfdale Dual Core E8500, 3.16G, 6MB, 1333FSB, 65W, C0
Wolfdale Dual Core E8500, 3.16G, 6MB, 1333FSB, 65W, E0
Wolfdale Core 2 Duo, E8600, 3.33GHz, 6MB, 1333FSB, 65W, E0
Conroe E1400, 2.00G, 512KB,CCO,M0
Conroe E2140, 1.60G, 1MB, 800FSB, M0
Conroe E2160, 1.80G, 1MB, 800FSB, L2
Conroe E2160, 1.80G, 1MB, 800FSB, M0
Conroe E2180, 2.00G, 1MB, 800FSB, M0
Conroe E2200, 2.20G, 1MB, 800FSB, M0
Conroe E2220, 2.40G, 1MB, PCO, M0
Conroe E4300, 1.80G, 2MB, 800FSB, L2
Conroe E4400, 2.00G, 2MB, 800FSB, L2
Conroe E4500, 2.20G, 2MB, 800FSB, M0
Conroe E4600, 2.40G, 2MB, 800FSB, M0
Conroe E4700, 2.60G, 2MB, 800FSB, G0
Conroe E6320, 1.86G, 4MB, 1066FSB, B2
Conroe E6420, 2.13G, 4MB, 1066FSB, B2
Conroe E6550, 2.33G, 4MB, 1333FSB
Conroe E6600, 2.40G, 4MB, 1066FSB, B2
Conroe E6700, 2.66G, 4MB, 1066FSB, B2
Conroe E6750, 2.66G, 4MB, 1333FSB, G0
Conroe E6850, 3.00G, 4MB, 1333FSB, G0
Conroe E7200, 2.53G, 3MB, WFD, 65W
Intel Pentium Dual-Core E5200(2.5 GHz, 800 MHz FSB)
Intel Core 2 Duo E7400 (2.80 GHz, 1066 MHz FSB)
Intel Core 2 Duo Processor E7600 (3M Cache, 3.06 GHz, 1066 MHz FSB)
In BOLD is your best option, Quads can not be installed on your motherboard:
The Inspiron 530 has two variants of motherboards, both made by Foxconn and based on the G33M series. The G33M02 which supports up to Core 2 Duo processors (the e8600 is the fastest compatible cpu)and the DG33M03, which supports up to Core 2 Quad processors. Inspiron 530 systems sold with Pentium Dual-Core or Core 2 Duo processors can not be upgraded to Core 2 Quad processors without adding at least a 350W power supply and swapping motherboards to the DG33M03 motherboard. The reason the G33M02 doesn't support Core 2 Quad processors is because it only has 6 voltage regulator ICs, the DG33M03 has 11.
If interested I will look into CPU cooler situation.
It would be the best to upgrade to 64 bit Windows, in this case you may utilize up to 8 GB of RAM, officially only 4 GB advised, however, I have instructions available on installation of 8 GB is needed.
Video Card. What is the purpose of upgrade, is it gaming? Or just regular use? If gaming, power supply would have to be upgraded to accommodate stronger Video Card, if regular use, smaller card can be installed without power supply upgrade.
Now, it is your turn.