need help,please

i have a 97 ga 2.4 and i am leaking water from where the water pump and thermostat are.i guess its the waterpump.i have the repair book,and it sounds like alot of work.has anybody changed this their self,cause i cant afford to pay to have it done,since the dealer charged me $800 to put one on in 2002.any help is well appriciated.thank you