Quote Quoting sphynx77
Unfortunately her Passport has expired. Is she considered being here ilegally now?
Her Panamanian passport? Her permission to be in the country comes from her U.S. visa, not her foreign passport, although it makes sense for her to renew her passport such that she has current evidence of her identity. She can check with the USCIS about any requirement to have her visa updated such that it is reflected in her renewed passport.

Quote Quoting sphynx77
What procedures do I have to go through now to marry her.
You would take the normal steps - get a marriage license, get married before somebody authorized to officiate over a marriage, register the license....

Quote Quoting sphynx77
Will she need to apply for a green card through marraige?
Once married, if she wanted a green card, it would make sense to apply to adjust her status. You would file an I-130 petition for Alien Relative, and I-485 application for permanent residence. Your fiance should obey all U.S. laws, including immigration laws, during the time the applications are pending.