You can buy a single ride for $2.00 or you can buy a $7.00 MetroCard good for four rides. There will be machines where you can buy a MetroCard. Follow those signs, they're clearly marked.

You'll red circles with the numbers 1, 2 and 3. When you get off the NJTransit train, you'll enter the main train station. Simply get off the train before Queensboro Plaza and wait for the next train which will be a local. The express trains are clearly marked and announced. You could take the 1,2 or 3 trains one stop to 42nd Street Times Square and get the 7 train there OR you could get a taxi for $20. Should you decide to take the train from Newark Airport to Penn Station, you could take the E train from Penn Station to Queens Plaza and walk. Please take a look at the link and let us know whether this answers your questions. We are presently discussing the best way to get from Newark Airport into New York City on the thread I'm providing the link for.

The LaQuinta is easily accessible from the 7 train, I don't think the hotel offers airport transfers from LaGuardia.

RooseveltL - Note that Hrdhitta isn't going to LaGuardia Airport but rather to the LaQuinta in Queens.

Newark airport to new york city train