Yes, you have to get a new valve.

With your small pool, the 1.5" model (SP715x or some such -- I haven't looked) will work OK.

The pump should be OK; you may want a timer if you don't have one, so you can save on the power bill.

Regarding plumbing . . . can you plumb 1.5" and 2" PVC successfully? Have you done it before? Often, when plumbing a filter, things get tight and if you don't have some experience, it can be hard to get them to fit together. Yours shouldn't be too hard, and doing so would give you a chance to remove the Hayward feeder and the Nature2.

Lemme know. Are you wanting just info on POOL parts, or on PVC layout, too?