Well it depends on what you want to spend of course. First off I am not 100% sure that your current speakers will fit. If they do then you will be doing well. I can suggest the Sony and Clarion stuff as good quality that will work well for you. The Sony will offer more if you want to do MP3 stuff.
Taking the radio out is a snap adn then you can buy the wire harness to addapt the new radio. You will also need a install kit. Good luck.