Hey Jeet
Welcome to the club!
311 in mock and without practice is a good start. With better preparation you can definitely increase to the best score.
You can find free test details here:
https://gre.myprepclub.com/forum/free-gre- ... ml?fl=menuRegarding the course, to take it or not will be a personal call for sure. However, you can find everything you need to crack the GRE on this forum. Feel free to roam. It will definitely be worth it.
Here are some course reviews that may be helpful :
https://gre.myprepclub.com/reviews/Feel free to ask for any doubts. We will be happy to help you.
Regards,
R