Finding the exact problem will also make it easier for a mechanic and thus cheaper for you. It doesn’t matter if you do not know the name of the part but it is always better to be able to point it out.
Finding where the leak is taking place is also a great start. Check underneath the car to ensure there is no leaking onto the ground which could be very serious. If you can’t see anything dripping, wait until the next time you go to your car and check the ground and note the position of the liquid.
If there is no clear indication of liquid leakage and it is merely just the scent of gas, you may need to change the air filters. Otherwise, fuel filters may also e need replaced.
If you are driving when you notice, make sure you have a tool kit with an assortment of screws. Stones may fly up and pierce the tank. Finding the hole should be pretty easy and inserting a screw can temporarily secure it.
Taking the car to its dealer will be more effective than just any old garage. They will know the car inside out so it will be quicker and parts will be more available. This will result in the repairs costing less.