Car idling at 1,700 rpm also clutch slips Celica 94 ST

Hows it going guys I have some minor issue right now with my car , i'm barely learning my car ,but okay i bought a new engine for my Celi i have a check engine light , and my clutch is slipping . Everything is fine in my car the only thing i can think of right now for the check engine light is my o2 sensor , but also feel like my techometer might be mess up . Then here's the second issue my clutch which clutch kit do you recommend for a celica st price range 130 and lower just want decent performance's one .