Two things:
1) You have a plane doing 2x. Perhaps you want to try lowering it to just 1x and, with the hours you free, find another route to put the same plane on. You'll probably discover that you make much more profit that way.
2) When you have plenty of flights from Manila you should indeed start looking for a second base. Now, you're renting gates elsewhere and each gate is good for 10 slots or frequencies. If your second base is not far from your first, you can fly to the same airports you're already renting gates at, thus saving a lot of money on yet new gates. Mind you, creating a base (other than the first one, for free) costs a lot of money. More precisely 50x the cost of each gate, plus you have to rent at least 4 gates there before you can create a base. So, it's not something you should do too early.