5 references?!

Ok I applied over a month ago for an OP position run by the mega hospital. (I used to work for this company at a diff hospital) First I was invited to fill out the personality survey, since I passed they now sent another email inviting me to understand their mission statement, she also mentioned that I need to have 5 references, 2 of which must be previous managers!

I have a problem with that. I only graduated Jun 2009. This is my 2nd career. Even though I was a manager at one of my previous employers it was a travel agency that went belly up and the owner (my supervisor) has died. My last travel job that was with a company that the manager is no longer there and I have no idea how to reach her. I "may" be able to locate info for her since I'm still friends with someone who still works there but it's a long shot.

My first job out of school was a LTR that I hated for how it was run. I was there for 8 mos. The DON I'm sure would not be thrilled to be a reference for me. I'm not even sure if my direct unit manager is still there. They were very upset when I left even though I gave them 2 weeks etc...I have limited contact (Christmas card literally) with one of the former co-workers that may know her. I have a great letter of recommendation from a another co-worker that has all her info sans her email that I have as copies and have hand carried on interviews.

My second job was at the mentioned hospital, I was there for 9 mos. Again the manager was very ticked I was leaving and even went so far as to try to stop my new job. (this is a mega hospital that owns many of the health facilities, as the norm in many places she could have held up a transfer for 8 weeks or more if it was owned by them, it wasn't and she was upset) I know her first name but her last name spelling truly escapes me. I never thought it was something I should have kept, again I don't know if she's there, I didn't stay in touch with any of those co-workers.

My present job I plan to use my current boss for a future reference as we get along great (I've been there over a 1.5 years) but I highly doubt it's wise to clue him in now that I'm planning to leave, although everyone and I kid not EVERYONE is job searching as we're not overall appreciated and it's very stressful.

My main references are my nursing instructors and as mentioned my co-worker from the LTR.

Should I try to figure out what my previous unit manager's name was and her info and hope she gives a decent reference? She flat out told me that she thought it was a huge mistake that I was leaving direct patient care in favor of an "office" position. (I do clinical review work) Like I said she wasn't pleased.

Any help or guidance would be greatly appreciated. I checked the job section to post this but it didn't really fit there plus there's no traffic there! Thanks!