New processor in old mobo

I urgently need help regarding my mobo.
Cpu-z shows my mainboard as
manufacturer - LDZU ELECTRONICS CO. LTD
model - I945 series
with intel chipset.
My cpu is an Intel celeron 331 (2.66 ghz) (codename prescott)
package - Socket 775 LGA

Now, my question is will i be able to put a new processor(like intel core 2 duo, quad) in my motherboard..

My e-id is indurkar.akshay@yahoo.com
Please please reply asap, as u guys are my only chance..

Also, can u guys please tell me which is the best value processor that'd fit in my mobo.plz plz, that would be so helpful.
The budget for my processor is 7000 indian rupees (around $130)
please please rply fast.
Or contact me on my email id..
Thanks a lot.