Volvo 480 heater problem, also service advice?

I bought a beautiful 480 es 1988 model in May 2004. 37000 miles ! goes with no problems. But im coming up for MOT in Feb, wonder if any one can advise where to go for service. I live in N London, drive it only around 2000 miles a year. Few problems,- heater runs ok for about 2 mins then packs up, water leak in passenger front footwell and footwell behind. Any info on these problems.. How much should I pay for a service? cheers