I am not exactly too sure of the TDP issue, but considering how laptops are like, I would avoid going for CPUs that are above the TDP of your current CPU unless you are fully aware that said laptop is capable of supporting said CPU.
You will also need to consider the IGPU since the i7-720QM lacks said IGPU. However your laptop most likely has a dedicated issue so this shouldn't matter that much.
You should also consider thermals since these better processors can run hotter.
I would recommend going for the i7-640M or i7-620M as their TDP matches that of the i5-460M.