I've been reloading and casting my bullets for years. KimberPB is correct, MidwayUSA has everything you need to cast your own. You can get wheel weights from tire shops and they work great for casting. Wheel weights are fairly hard and if you can find some tin or Linotype you can harden them even more. Dropping hot cast bullets into cold water will make them harder also. Using Gas checks will help you get higher velocities. As far as Lead fumes causing problems don't worry they won't. Like said above it has to reach the boiling point before it will release fumes. The boiling point is 1740.0 °C or 3164.0 °F. The only worry when working with lead is to make sure and wash your hands so you wont ingest any.
USAF Retired, CATM, SC CWP, NH NR CWP, NRA Benefactor
To preserve liberty, it is essential that the whole body of people always possess arms, and be taught alike, especially when young, how to use them... -- Richard Henry Lee, 1787