First things first... New oil can sometimes quiet down some of those noises unless it's something really serious. So, do an oil change if you haven't already.

Have the valves ever been adjusted on the car? If the previous owner was irresponsible, then most likely not. You should look to do the valves every 30-60K depending on your particular cars needs, etc.

Valves are easy-breezy. Just get a Haines manual for your car and look in there for the specs. All you need are some sockets, a feeler guage set, a new valve cover gasket, and some high heat gasket sealer for the corners of the gasket, etc. Try that first. If the issues still persists then it may very well be something larger. Just work your way through the easy, and more importantly, cheaper stuff first.

HTH.