Extend my mother's visit visa

Hi guys,

I need your help....

I am married to British citizen and I am from Egypt and I have leave to remain visa expire on August 2016. My mother is visiting us on a 6 month visit visa. It is valid from Feb 2015 to Aug 2015 however she didn't actually enter the country until April.
We would now like to extend her visa so she can stay a couple of months longer. Is this possible and how do we go about it.

Another questions,
If we can't renew her visit visa when will my mother be able to apply to visit us again.
if I apply 2 years visitor visa for my mother, what are the restrictions of the visa visitor, what I know she should leave before 6 month, and someone told me she can stay only 6 month every calendar year.

I am so confused please help guys.....

Thanks
Hano

No - u cannot extend a VV, expect in compassionate circumstances, i.e. Civil War or Tsunami so forget that...

You won't get 2, 5 or 10 year VV without several trouble-free six months visas first...

Rules are 'genuine visitor' - rule of thumb has always been 6 months in every 12 but even then, 6 months in every 12 is not visiting - its being resident half a year so you need to be prudent.

It may be possible, but very expensive.