Problems with my 1.4 TDI Polo

[...Mole...]

ive had my 2001 Polo TDI for around 2 years now i am planning on selling it soon, however it has some problems that i would rather sort out first. first one is that it over-revs quite a bit usually when it gets to abou 2500rpm which only started happening about 2 months ago. Also occasionally i get the water light flashing and i have to let the pressure off and refill the lost water that spills out during that, this dosent happen that much maybe every 2-300 miles.
the car is at 121,000 miles so i expect problems from it just wondering if any of these would be easy fixes as im prety much broke.

also anyone know where i can get a replacement wingmirror as someone ran into mine whilst it was parked on the street >.<

thanks