Sorry to say, but in my state at least, the only legal way to deal with this is to hire a crew licensed to deal with lead paint removal. You can paint over it, if you want, but you will need to disclose knowing about the lead paint when selling.

Honestly, this is not something you want to be penny-wise-pound-foolish on. Have a remediation crew that knows what it is doing take care of it for you and your family's sake.