Hi,
You have an average profile but you can make your application strong by working on few things like achievements in your job, GMAT Score. You should also make your contacts with the alumnus of Business Schools you are targeting and based on the requirement you can improve on your extra curricular and GMAT Scores by the time you will apply for MBA.
For online GMAT Preparation you may visit
https://tinyurl.com/cp46f9xYes, you are right for most of the US Business School R2 deadline starts from Mid December- early January. I would suggest you instead of applying in R3 you should target applying in R1 and R2 if you are ready to take your GMAT in Oct month. As per your profile and age I would say even if you miss the deadlines of few business schools this time you may apply next year as well as most of the business school see the overall profile along with your GMAT Score and number of work experience. So, by the you will apply for MBA you will have good GMAT Score and a good amount of work experience as well.
You would need to cleverly prepare yourself for questions like the reasons you want to apply for MBA, your rationale behind applying for a specific B school, so on and so forth.
The next step for you is to focus more on your GMAT and application essays, recommendations for these Business Schools.
Please visit
https://tinyurl.com/cnpsl4a to see more about online Essay Evaluation and Interview Preparation.
Feel free to post any other query or concern that you might have.
Cheers!!
Neha Singh