A 1.5hp pump is probably too large unless you have 2.5" (ID) or larger plumbing. If it is very old, don't waste money rebuilding, get a new pump, you'll be happier in the long run.

For your filter, you will need a grid set (7 full and 1 partial grid), possibly a manifold, air-relief screen, tank "O" ring. If you don't know the size of the filter, measure the tank height with the lid on. Give this measurement to a pool supply and they can get the correct grids.

Is the tank-clamp there? If not, and you need all these other parts also, it might be better to get a new filter.