Any v-belt of the same length width and depth will fit...radiator shops, auto parts, Ebay, etc. Get a high quality rubber cogged belt if you can.
You might find a handwheel on Ebay, or you can even place a want ad in the free classifieds.
There were many iterations of this saw that were very similar, so there are many versions of the manual that should offer some help. In addition to the Emerson made Cman contractor saws (113.298###), some of the Ryobi made 315.######, and likely some of the Emerson or Ryobi made Ridgid contractor saws (TS2412, 2424, 3612, 3650, 3660) have very similar guts. You may find that many of the parts you need are interchangeable, but always check first before making an assumption.