I'd split the difference and get a 470. The 1050 Ti is a bit weak for what you want, and a 480 costs more than the 470 and won't really do better for you. Make sure your power supply can handle whatever you decide to buy.
Find online specs on the card you like, the measurements should be in there. Then measure the space in your case. Measure the 730 you have, compare the larger sized card to that, you can see how much extra room you have.