Hi - there is a big thread above running on it which if you have the time is worth a long read but...
I'm assuming it's a 2010-12 ish year?
The engine is designed to use a certain amount of oil - mine does - it's when it uses too much that you have an issue.
The best experiment is to top the oil up to maximum & reset the odometer to 0
If the oil top up warning comes on before you have done 600 miles, the above long thread is a must read for you.
If the oil top up warning comes after you have done 1000 miles, then you probably don't have a problem.
Inbetween those mileages, then keep an eye out.
I would first mention it to the dealer you bought it from, so it is 'logged' with them and they know you maybe coming back with the car.
Audi did honour fixing the oil issues with the 2.0TFSi as it was an engine defect. Although yours may be too old or high mileage for them to do anything. I think it was piston rings!? I know some had oil pump issues.
What year and how many miles? How good is the service history?
Unfortunately those 3 months warranties are usually worthless, especially if the dealer isn't the best. They will only cover actual engine failure and don't cover worn items, like piston rings or anything electrical. But having said that, I had a car with a slight head gasket leak and the dealer honoured the warranty and fixed it. They also fooked the engine after that and then had to strip the engine and replace bent valves etc, so probably cost a whole lot more than a standard head gasket replacement!!