1996 Volkswagen Jetta Coolant light

Hello my name is Danielle and I bought a used VW Jetta w/169000 miles for 4000$. And the exaust pipe was rotted within a month. The fellow who sold it to me fixed it for free but at first saying that a fitter was a VW part that was supposed to be there is this true? Also my coolant keeps leakin I went thru a bottle in less than a month any idea whats wrong so I no when I take it to the shop? Thank you very much