Will Wattage this be enough for my 750Ti?

depends on your system.. but probably... depends on the 12V rail of your psu...

that is a 60W gpu... unless you got a bunch of hard drives and disk drives and fans and some overclocked 120W cpu... you should be alright.

I know the 750ti is generally ok with most above average 300W psus... as long as your 280W psu isn't junk it should be ok.