i would have to say they would be very low light corals to give it a go with that light...do you have the light already? that sounds like a 24" fixture, which maybe too small for a 45 to get adequate light output..only 28 watts into 45 gallons...that is about 1.6 watts per gallon, and though people dont like to go by watts...i still think 5 watts per gallon is necessary for corals..
on that note you should be fine with some mushrooms. polyps, maybe some leathers, and some colts or kenya tree type corals, you might even get a hammer to grow at the top of the tank...but i dont think any will be very happy...
that is just my 2 cents though...
you can find cheap....cheap mogul based 175 watt Metal halides anywhere with batwing reflectors that would light your tank up very nicely though and allow you to grow and keep most corals happily..atleast to get you going until you can afford better/ more expensive lighting...
T5's are great dont get me wrong...i just dont think you have enough...