Vostro 200 or Inspiron 530 desktop require G33M03 motherboard AND 350W power supply.
Since you don't currently have a quad I can note that you have 305W
so the answer is still no.
The FoxConn DG33m03 [Dell P/N OFM586/G33M03] motherboard, with a 350w PSU, should support the following:-
Yorkfield Quad Core, Q8300, 2.50GHz, 4MB, 95W,R0
Prior to installing the processor check that you have BIOS Version 1.0.15, or higher installed, when support for new Intel CPU's was added.