I was wondering if there's a way to search for a range of numbers in the bet history. So if I'd like to see all bets between 99 and 100 how can I do this?

You can use normal sql wildcards to search using the search function in the bet history window.

Go to View-> Bet History. In the top left corner of the bet history window, select the search option from the drop down. Tick the roll checkbox and enter your requirements. For rolls between 99-99.99, search for 99%. This will not search for 100 bet everything else you need.

Otherwise, use sqlitebrowser to access the database directly and perform a query there with your criteria.