If you have been out of UK over 2 years then your ILR could be in trouble. But even then you can get the returning visa. See the link below:

http://www.ukba.homeoffice.gov.uk/visas ... residents/

As long as you have ILR and you are coming back to UK within 2 years, you should be fine.

She needs to spend two years in UK with you. I think you will need an extension for her and once she has completed 2 years, she can apply for ILR.