Welcome to the forums and prewar card collecting. Here's a couple useful tools, the first site is free but not as thorough as the 2nd one which requires a subscription. The 2nd site does offer a one day subscription for only $4 which is well worth it when you're considering a card that will be in the hundreds of dollars. Good luck! The search for the right card is 1/2 the fun!
http://www.cardtarget.com/
http://www.vintagecardprices.com/