It is possible to make elemental bromine from a mixture of potassium bromide, H2O2 and a little sulfuric acid. However, it is NOT recomended as bromine is evil to work with, and especially distilling! Swim has successfully distilled bromine from that mixture before, but the entire glassware, exhaust pipes etc are next to impossible to clean afterwards. 3% H2O2 is also a little bit to diluted. 10% is probably better to use.
But you can do the reaction in situ, meaning that you add the whole thing(2CH, GAA, KBr, H2O2, Sulf.Acid), but the yeilds are not terribly good afaik. Read up on the oxone reaction with bromine. It should work perfectly for your needs.
Regards
Bandil