Spending more to potentially make more

It's hard to explain what I do but recently I spent around 2.5K to create a video game on the platform Roblox, the game is doing well and at it's current rate I would make my money back in around a month but the game needs some work on some specific parts to help increase the potential of it which could cost around 800 USD at least. Not sure if I should spend the money here or not any advice?