94 Celica ST engine question?

Ok I am buying a 94 Celica ST off a friend of mine, $1000. There's a new radiator, distributor, fuel pump, clutch, and a used but good condition alternator. I was hoping to prioritize on parts needed but I dont know much about Toyota engines or this make at all, infact its my first car. It has the original 4-cylinder 16-valve engine so it must be losing hp from age and I was hoping to get it back to its original hp if thats possible, not trying to break any records here but would like to get as much hp back as i can without swapping engines or going crazy with modifications. Also, I just looked at the title while writing this and its listed as 161k miles, if that helps. Thanks in advance, and happy driving.