I just bought a house circa 1753. Of course, now that I've paid for it, I find the termite damage. There are two spots of concern. One of the beams in the basement was eaten about 1-2 feet in from the wall. The other I can only see in the floor boards above the foundation, but I fear they ate the sill on their way or even worse, they may have gotten the corner post.

What I wonder is: what are the techniques to repair these three components (beam, sill, and post)? Is it something that can be done by me or my wallet ?

It also appears that other parts of the sill have already been replaced but some of the beams no longer rest on the sill, but instead upon the foundation. Should I be concerned about that?