Hey, you can improve your knowledge by reading Bhagavad Gita book. But, in this short period reading the whole book needs more time.
There is another way where you can learn is by an application named "Shrimad Bhagavad Gita and Gita Saar in English" from Google Play Store.
The application consists of 18 chapters/Adhyayas and there is a Gita Saar also. The best thing is that the whole Bhagavad Gita is in English. So, you no need to find the meaning of sanskrit Shlokas.
The application has some amazing features like
1) Quick Read- where you can quickly go through the chapters.
2) Mark As Read- Mark the chapters as Read, So read new chapters next time.
3) Bookmark- Add the chapters to the favorite list which you loved it and many more features.
Hope, this works for you!