JOdowd is right, you can buy it online. Personally I'm lucky enough to work with a packrat. I told him I was interested in pouring my own jigs and needed some lead. He said, "How much you need?" I said three or four pounds. Next day he comes in with 36 pounds!!!! of lead buckshot!!!! LOL Needless to say I'm set for the forseeable future.
I forgot about pouring the blanks like cadman said, this helps too. but it does sound like your lead may not be hot enough if everything else isn't working. i usually let it sit for 20-30 minutes after i turn it on.
Also if you are close to a Lowes, go to the plumbins section and see if they have any lead flashing. it looks like a small traffic cone but and it's made out of soft lead. the Lowes here has them for 49 cents a piece so you may want to try there. not sure what shipping costs will be if you buy a whole lot online. i also know that bass pro and gander mountain sell lead ingots.