good fast lens for low light sport?

Hi Guys(and gals)
I'm doing more and more sport shooting for the local paper/website. I've been lucky to hit a few indoor sports, recently fencing, archery and boxing, and have muddled through with a combination of flash (where allowed), and my manual 50mm produced a few accepatable shots of the archery and fencing grabbed).

Been happy (and profitable!) with what I have produced so far, but I do need to have the flexibilty of a fast af lens. Ideally, per my "mentor" at the paper, I guess somewher in the order of 24-35mm, able to hit f/1.7 with a nice fast responsive af.

Am just coming out of unemployment, so money aint exactly drippong off the trees but am committed to getting this now as its gonna enable me to widen the scope of jobs i can go on

So, any suggestions of a suitable lens?
I do want a new lens, unless someone has one out there they are thinking of updating?

This is stage one of my increasing collection - down the line is a fast prime telephoto, around the 400mm+ mark - but that may wait for the lottery win!!

K20d, 18-55kit, 75-300mm, 50mm f/1.7 man, macro tubes, flash, manfrotto tripod, corel psp,
and a whole lotta learning still to do!

Sigma 30mm f/1.4 would be your best bet, there aren't that many fast lenses around that range.

The Sigma is probably your only bet under £500 - the only lens Pentax made in this bracket was the 35mm f2, which wasn't as fast as you need and is in any event out of production.

For the sake of another suggestion, the Sigma 50mm f1.4 has a reputation for being notably sharper/more contrasty wide open than manufacturer own-brand equivalents - you'll already know whether the focal length is useful, and this has both the ability to go wider than your existing lens and also has HSM (silent motor) autofocus. If you are interested, make sure that you buy it from a retailer that pays return postage on faulty items - your chances of getting one that DOESN'T front focus are less than 50% according to one estimate.

If you've got cash, the 31mm FA Limited f1.8 is pretty good as well. I've got the Sigma 30mm f/1.4, but I've not been able to use it much (I loaned my SLR to a friend who is taking a trip down under). When it comes back I'll give you my feedback on it.

Just to say that I of course meant wider aperture, rather than wider in focal length terms

Thanks guys - am now planning the save for the sigma. very impatient though - after all there is a credit card on my table.......