I have a problem... of choice

I have an assignment in Berlin 3d and 4th weeks of July and also two weeks in september.

It's some kind of written reportage (maybe a book as well) over bars, clubs, restaurants and multicultural life in some parts of the town: Kreuzberg and Neukölln.

I'll need photos as well.

The photos will mainly be outside photos from the different bars,clubs restaurants but also ambiance photos at night inside several bars.
I will also need to do a little bit of street photography.

I need new material: until now I made photos (mainly in "P" mode) with the Lumix LX3; so, I'm not very experienced.
Having an art background (painting mainly), I'm not too bad in composition.
I need a small camera, no DSLR.
I have a budget of approx. 3000 euros (+ - 3700 USD) for the material.

First I wanted to buy the Fuji X-pro with 35 and 18 lenses (very good IQ and high ISO quality) but , luckily or not, the shop had sold the 2 models they had in stock; since then I'm thinking about the OM D EM-5, because the good diopter correction (I wear reading glasses) and the probably smaller learning curve.

Do you think it's a good choice and also, my main question: what lens would you suggest for inside photos in bars at night in low light and if possible without a flash ..?

Thanks for your help.