Really smelly urine isn't good, wees should be pale (not yellow staining on the nappy) and innoffensive smelling, so she really doesn't sound like she's getting enough. I agree with Janie, give her the breast first all the time. There isn't any one particular formula that will beef her up - different formulas will work differently for different babies - I had 2 of mine on the same one and one was a huge weight gainer and the other wasn't but bare in mind that compared to BM any formula will be harder to digest and the gold ones are particularly rich - which isn't necessarily a good thing and could possibly give her gut/digestion issues.