Please help

I have a very slight water leak coming from above oil filter, think its the seal gone on my water pipe?, where do i get the seal from, or does anyone know the size...im useless at cars, but am trying lol...all help would be much appreciated

many thanks

FIAT or ring Big Mick at eurocarcare in Drrby. (Google will find) VIN no. at the ready, as the part did change.