Leaky rear shock - service or replace?

As the title suggests I am loosing pressure in my rear shock, a fox float R. It's on my 04 Stumpjumper and will be coming up to 5 years of abuse this year. It is a very gradual thing but its a pain. Is it worth servicing? or getting a new one? Looks like I need a new wheel set too so it could be a costly time especially seeing as I actually want to buy a new bike, Mountain and Road.