Picking a formula??

My babe is 10.5weeks, normally breastfed.  we have introduced a bottle at least 1 time a day for three weeks now and now starting to move to two times a day because it is time to wean her off breastmilk and I don't have a lot of stock at all.
unfortunately she suffers from really bad gas
We are going to start introducing formula this week and I wanted to know which brand you suggest?