You could always add another pumping session or two in...it'll give you more freezer stash. Plan to pump about an hour after a nursing. Your body will respond my producing more milk and he will receive enough from you.
Ditto! I would work on pumping a few more times a day, if you do, your supply should increase enough and fast enough to get what you desire. BTW, you don't have to clean your pump after every time you use it. Maybe pump once, put it in the fridge and pump again after the next feed. Then freeze this.
The formula is a tough one as a lot of bf babies don't like the taste of it.... and you aren't going to like this, but usually the only way to introduce it is to do about 75% breastmilk and 25% formula for 3 days, then change the ratio to half and half for three more until you get to full formula. My lo did not like the taste of formula and it took awhile to get one that he liked, even doing what I just suggested. But you never know, you may be lucky and find one that your lo likes straight away.
Again, I think pumping more is the key. Drink lots and lots of water, relax, concentrate on your lo and pump, pump, pump. Even dry pumping increases the supply. Can you pump while you nurse? This is the best apparently.
Good luck.