A-Pillar repair

I have a 74 Dart Sport that came with a qtr vinyl top. I've removed it and found rust on the driver side, along windshield chanel and on upper a-pillars. Looks like the a-pillars were filled with lead. Has anyone come across these problems and how do I go about fixing them. I'm just learning how to weld and I don't know how to fab pieces yet. Any help would be appreciated.

2110,
If you could post a coupla pix of the area that you are talking about that might help members give ya some help on how to fab up the pieces you need to fix. Good luck. L8r

Jim