Buick Century Starting Problems

I have A 1994 Buick Century 2.2 And i just recently bought this car and the lady that i bought the car off of said that it had a blown head gasket so i replaced the head gasket and the car ran fine for a few days but then i noticed that the battery power was decreasing and i asked the lady about it she said that she forgot to tell me that the starter was bad in it so i had to replace the starter but when going to take off the starter i relized that the bolt was stripped so i had to cut the lines and i thought that i had the lines hooked up correctly but i dont know if i do but anyways the car will turn over now but theres a problem when i go to start the car i have to have my foot on the gas and the key turned over but when i go and let go of the key to allow it to go back to the run position the car shuts off and so does the start can anyone give me any help please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!