Hey Dan and welcome to the forums. :dance:
If the car is all straight or close to it, I'd personally do a full service before anything. Just the normal motor oil change with filter, flush of coolant along with the change of thermostat, gearbox oil if you're up for it and might as well do the diff oil.
As for modifications to the car, I went with modifying my suspension first to give it a nicer, lower look. It needed a change of shocks anyway so thought why not.. It really depends what you intend on using this car for though.
If you're just after a nice daily rider, a nice set of speakers and head unit would be up in the list of modifications whereas if you wanted to hit the track, you'd maybe go suspension first.
Getting power out of an NA car will be tough without money. Have you considered a 4AGE conversion or do you just want to keep the standard 4K-C motor?
Enjoy your stay. There's plenty of information around on this site.
Cheers