I have 3 boosts left and if my boosts have gone how can I get more boosts?
Hello! 
Boosts are a premium currency that are distributed to Pro members every month.
It is one of the several ways that we say thank you to Pro members for supporting WeMod’s maintenance and development - by giving them more control over what trainers get developed as a priority.
If you had WePoints from the older, less efficient trainer voting system in the past, they were converted into boosts.
From our support centre:
What are boosts and how do I get them?
Boosts are used to influence the priority of games in the queue. The more boosts a game has, the more likely it is to be worked on sooner than games higher up in the queue. After boosting a game, you may not see a change in its position until a member of the WeMod team reevaluates the order of the queue.
Boosts can mean the difference between us working on a game next week instead of next month. Since they hold great influence over the games WeMod users can cheat in next, boosts may only be obtained by Pro members. By supporting us with Pro, you get a set amount of boosts per month to use on any games in the queue. You also have the option of boosting a single game as many times as you’d like.
If you previously had WePoints or votes in the old app, they have been converted to boosts and may be used regardless of your Pro status.
Quote from: (Game Queue)