Dell inspiron 1545 laptop hardwere upgrade

You cannot upgrade graphics cards in your laptop.

Most of laptops aren't upgradeable including yours, so you stuck with your current laptop, sorry buddy...

well my friend it is pretty expenseive to change the vcard to a laptop. but it can be done with the 34 mm ExpressCard slot port that your laptop got you could add and external pcie port. check this :
http://www.villageinstruments.com/tiki-index.php?page=V...