Coolant is the mixture of water/antifreeze, which as the name suggests cools the engine, if you open the bonnet you will see a see through tank on the right hand side (Drivers side) of the engine bay. The level should be up to the max mark, which is printed on the front of it?

Worst case if it's the pump, is the labour (If you aren't doing it yourself) the pumps have plastic impellers can break, although it shouldn't be a particularly difficult job.

Martin