Hi Jackal, that's a nice set of lenses you've got there...
I'm not sure there's a 28mm f1.4 though - well not from Canon anyway. The models I could find are as follows and by clicking them you'll see their prices in the US as an indication.
Canon 28mm f2.8 USM
Canon 28mm f1.8 USM
There is an f1.4 model, but it's a 24mm focal length and a premium L version.
Canon 24mm f1.4 USM L
So it all depends what you're after and how much money you've got to spend - and more specifically given your already impressive kit, where you're finding it is lacking.
Fixed focal length lenses normally deliver better quality than most zooms, and also tend to be smaller and lighter. The big advantage for you though given your 17-55mm f2.8 is the opportunity of an even faster aperture, such as the f1.8 or f1.4 models. These gather much more light and will let you shoot under much dimmer conditions.
If you're finding the 17-55mm isn't bright enough, then yep, I'd recommend considering a bright 28mm - or a 50mm f1.8 / f1.4 if you prefer a longer focal length.