Tier 1General PWS Dependent visa from india

Hi All,
I have query regarding tier1 General PWS dependent visa from india(entry clearance).
My wife(tier1 general dependent) and kid was here in dependent visa,last year in sept 2011 and due to pregrency she went to india,now she is india ,and now tier1 visa expired on last month sept-2012 , and i have got my extension till 2015.
I am planning to apply for my wife and kid from india ,in oct2012.

I just saw the point base guideline:
The 28 day period of overstaying ,i am not understanding.
I am not clear ,will this impact to my dependent visa.
could you please explain.
http://www.ukba.homeoffice.gov.uk/sitec ... olicy1.pdf

Also Could you please suggest me
Currently i am staying in shared accommodation and i have received singleroomate tenancy aggrement from my landlord.
Could you please do i need to take a 2 bed room house before applying visa.I am planning to take the house once my family will back to uk in another 3 months.Please suggest what is the rule for the dependent visa regarding accommodation?can i provide in a covering letter stating that i will be accommodating once my dependent will back to uk.?Please suggest.


also please suggest me what are the points and best practice i need to consider.

Thanks very much in advance.