Upgrade CPU for Dell 1545 Inspiron

Looking to upgrade my Dell laptop and would like to get the best CPU upgrade.

The following are the actual laptop specs:

Made in 2009, 15.6 inch screen, 8GB RAM, 500GB hard drive and right now, the CPU in laptop is a Pentium (R) Duel-Core CPU T4500 @2.30 GHz 2.30GHz.

Also, if any knowledge or reference can be provided if this specific Inspiron could handle an INTEL I3 Quad Core CPU??

Thanks for any helpful response(s) or recommendations, etc...

kleis