I'm looking at rentig/buying a new lens for weddings

[Photog82]

So far, we have gotten by nicely with the lenses we have now but we are shooting a wedding at the end of the month that is going to be inside in a semi-dim room. To give you an idea, this is the location.

I was initially looking at the Canon 24 1.4 but thought that it would be too wide at a distance. I normally use my 24-105 with by 580EX II and it's worked OK in churches- I love that lens in a studio and outside but am not sure if it's right for churches and halls.

Any suggestions for Canon lenses for me to look into? My current lenses are in my profile. I'm leaning towards the Canon 50 1.4 L or the 100mm Macro IS L 2.8 as I can use that for close ups and portraits as well but how well would that work in dim lit rooms?