1999 Dodge Neon engine is burning oil

I've owned this car for like two years now, and six moths ago it started leaking oil and somebody told me to put an additive to fix the problem. It did fix the leak, the problem now is that it burns oil, I have to add 2 qts every week, also whe I turn on the heat I can smell it and when I get out of the car the smell coming off the engine is bad. Any suggestions? Thanks