The answer to your question depends in part on her intention. In a chapter 7 bankruptcy one option is a surrender, in which she "surrenders" her right to the property and the chapter 7 discharges her obligation on the mortgage. If this was her election, this would be reflected on the "Statement of Intention" in her bankruptcy filings. Then, it is up to you to have her leave and proceed with your attempt to modify the loan and move back in.
A chapter 7 can not address the arrearage that you indicate exists, and so the above scenario is the most likely of the scenarios likely in a chapter 7 bankruptcy. Why don't you talk to her and figure out what her intentions are with regard to the property. If you can amicably work out her departure, you will save yourself an eviction.
After a year of non payment it is possible to work out the mortgage, I have seen worse in this economy. However, you need to start talking with the mortgage company ASAP and pay as much as you can "up front". My recommendation: do this yourself. Do not hire one of the companies out there offering modification because many of them are in fact scams.
This answer is provided for informational purposes only. Actual legal advice can only be provided in an office consultation by an attorney licensed in your jurisdiction, with experience in the area of law in which your concern lies.
Absolutely! The issue you are going to have is working out the arrearage with the bank.
In Florida the chapter 7 filing has no impact on the mortgage terms, those stay with the house. By filing the bankruptcy, she has left you alone to work with the bank, which actually improves your chances of getting them to work with you. Be prepared to bring some cash to the table.
I agree with the previous answer to avoid the law offices and companies that you pay to negotiate a HAMP modification for you. 95% of them are scams. There are legitimate housing counselors (always go with a non profit) that can help if you can't do it on your own. I would try doing it on your own first.
If you nor she have been served that is good. Within the chapter 7 she could reaffirm the loan on the house - however, she normally will have to come up with the back payments and then not default after that. It is possible that you can work with the bank to get up to date on payments and take responsibility for the mortgage. You can even talk to them now - since they can only talk to her atty - but you are not in bankruptcy. I really don't think you need one of these modification companies - my clients have had absolutely no luck with them and spent small fortunes before coming to be for a bankruptcy.