Ammo is a "personal" thing -- in the sense of its intended use and what works best in a given gun. (Two P-95s, coming down the assembly line, one after another, may have different performance with the same ammo.)
Try several different brands.
I had (sold it, regret having done it) a P-95 and used Sellier & Bellot for practice at the range, and Golden Sabre of comparable weight/power for concealed carry. If you buy in bulk, Sellier & Bellot can be very inexpensive -- around $6.00 a box.
Its a very good gun, and one of the best bargins going...
Think about getting a trigger job...
After-market magazines are a crap-shoot: some will work beautifully, some won't. Your best bet is to stick to Ruger-brand magazines, but, if you can find some cheap 15-rounders (any 9mm magazine designed for the P-series pistols should work), take a gamble.
You're stuck with the grips you've got. This is a polymer frame gun and you can't change the grips. But, you can get the slip-on (Hogue Handall, et. al) grips, and they help reduce slipping, etc. They don't reduce recoil.
Night sights might be a nice addition, later.