Using WPA and WEP on a WiFi?

Just bought a new 11g router, but I already had an 11b PC-Card in a
laptop previously. The new 11g router has the newer WPA encryption. The
older 11b laptop card doesn't do WPA. Now does the WPA have backwards
compatibility to WEP? What I mean is if I set the router to WPA, will
the older WEP-only card still be able to work with it?

Also how safe is WEP from decryption? I understand that there is a
vulnerability in WEP, but is that vulnerability only against the
basic-level 64-bit WEP? Does the enhanced-level 128-bit WEP suffer from
the same problem?

Yousuf Khan