Adequate Maintenance: FLR (M) Help Please

I am lost browsing through so much information.
Still cant make clear sense of things.

Could anyone please extend a helping hand.

I got ILR September 2011.
I have a wife and three children (all UK born, the last one born last month).
My wife is still on Tier 1 PSW dependent visa.
She originally came here to join me as a student dependent in March 2007 and never left the UK.
She recently got her English Certificate so we can apply for her FLR (M).

I am self-employed and currently earn about £2500 a month.
I also get Child tax credit/working tax credit (about £189 per week, though may decrease when I do my last year tax return) as well as child benefit.

We live in privately rented 3 bedroom house and pay a rent of 800.
Council tax will probably will be another 150 max per month. (we just moved in)

My wife is also planning to work after as soon as it becomes possible.

Now, could you guys please work out for me if the above is sufficient maintenance to apply for my wife's FLR(M).
Also how many months bank statements do they require? I couldnt find clear guidance on this anywhere.
I will apply before the 9th of July, though would be nice to know after 9th July scenario as well.

Thanking you all in advance.