Ok so I'm shooting a conference in a fortnight and I'm thinking I need the 85mm. I don't have it and I think it would be a good addition especially for a low light environment.

I'm also new to Brisbane and have been out of the scene recently so looking for somewhere to purchase or am I still better buying online. Any recommendations would be greatly appreciated as well as thoughts on the 85mm. I really want the 1.4 but can't justify the cost.