If you wanted to express then that's fine, it's not that expensive to buy a pump. If you only express once a day it shouldn't cause problems with increasing your supply to a ridiculous level and it would just take the edge off the leaking.

If you still leak, you could try something like Lilypadz, which are sticky breast pads that create pressure so you don't leak. That CAN affect supply in the early days, I have heard, but that isn't an issue here so go for it.