ABS pump leak....

[symun]

Thats what has come up on my vcds lite.
ABS light comes on once brakes are used, tried switching the fault off and it came on the next journey.
I thought it was a sensor so i put my vagcom on it and thats what came up.
Its my missus car that i have already put too much money into, is it a hard/expensive job to replace.
Its a 1.6 T reg polo...