My Octavia has just done 100,000 miles and because I am uncertain what it's service history is I thought it's time to change the timing belt. Do I just change the belt at this mileage or do I have to change any of the pullies?

I also what to change the oil again but I have forgotten what oil I used llast time, can you remind me what oil to use.

The car is a 1.9 diesel glx, engine code AGR.

Full timing belt kit, includes various pulleys and tensioners. You might want to replace the water pump when the timing belt's off (fifteen mins to do now, as long as a timing belt to do later).

What does a full timing belt kit and the water pump cost?

vag parts is a good place to look for parts