According to steemd.com, it looks like your RCs will be back to fully charged (if you wait and don't do anything else) in 20 hours. You're sitting at just under 83% of use at this point.
However, as the amount of RCs you have go up, you'll reach a point where what you're using them on—upvotes, comments, posts, etc.—won't affect or reduce them as much as they do now. So, charging will appear to be faster, even though it's more a result of the activities you're doing no longer exceeding the number of RCs you have to handle them.
I suppose the same thing happens with voting power, too. Every one hundred percent upvote takes a constant amount of time to replenish, but with more SP comes the opportunity to split upvotes into smaller weights and still allocate a significant amount. At what point that happens, I don't know, since I don't feel like I'm there yet, but as far as RCs go, where I am currently as a small dolphin keeps the RC levels almost always above 99%.
It may take some time to get enough SP/RC built up to do more on a daily basis, but it eventually does happen. Participating in contests as much as possible and getting involved with different communities can help. If at all possible, and if you want to, now is still a good time to buy STEEM while the prices are still low. Even something like $25-$50 might show enough RC improvement to make a difference.
Getting to 200-250 SP should do the trick for most users. Any decisions to buy STEEM, however, are purely up to you and how you want to go about this. Trying to obtain a larger delegation is an option, too, but it's something that isn't permanent and depending on the arrangement, something that could end at any time.