Upgrading from 10.5.8 to 10.6+ without an operating CD/DVD Drive?

Hi there, I own an iMac Intel Core 2 Duo 2.66 GHz 4GB 800 MHz DDR2 SDRAM, Early 2009 model, on OS X 10.5.8 and I definitely need to upgrade it to at least 10.6, since many things such as Flash Player, YouTube and several Apps are not running on my system. My CD/DVD drive has stuck a long time ago. It is neither a software issue, nor I am sure whether it is a hardware issue exactly as the CD has stuck in and it wont eject because the case has been harmed outside and it will not let the machine pop it out as it does not go out through the "hole", it bumps on the metal. I guess this requires a more specific repair which I cannot afford at the moment for such an old machine. Is it possible to upgrade using an other way? I do have the Snow Leopard setup disc but I cannot insert it! Maybe via an external CD/DVD drive? Please help! It will be very much appreciated. Thank you in advance!