Actually no, they cannot. At least not the firearms stuff.
Um, what do you mean? They can cram in whatever "firearms stuff" they want that is permitted under Heller, which allowed for regulating weapons that are "extraordinarily dangerous" and restricting possession in a number of different areas (arenas, schools, medical offices, etc.).
So for example, the ATF may no longer be able to make arbitrary and capricious rules about the import of certain firearms that they feel violates GCA '68. But Congress can still pass an arbitrary and capricious bill like 922(r), or slip similar language into whatever must-pass bill is being considered at the moment.
Without a doubt, we've received two very good decisions in the past week. But the price of liberty is still eternal vigilance.