That's PSU not UPS.
I don't see where having a larger HD will make any more demands on power than a smaller capacity HD. In most cases they should stay the same for similar physical sizes. However, if you added a 2nd HD to the original HD, then that will add more demands but even that will be minor. However, the 300W PSU is typical of HP systems and it wouldn't be unkind to replace it with a higher wattage unit just to be safe and happy for the long run. Since, you've replaced the HD in question, you should at least recheck your work and all the connections to be sure they're OK.
I have an HP Pavillion desktop (model P6157c). I recently replaced my hard drive to a 2TB Seagate Barracuda Green hard drive, 5900 RPM 3.5 Int. ST32005N4A1AS-RK. I'm having problems loading the startup discs. Someone told me I needed a larger UPS. My current UPS is a LiteON model PS-5301-08HA, 300W.