Letter of Recommendation

I am a new grad and like most I have been having a difficult time finding my first nursing job. Monday I had an interview for a new grad position and it went very well. I actually ended up interviewing with the HR person, then two people from the Education Dept that head up the New Grad program. I am very excited! However, they can't move forward until I have two letters of recommendation (has to be from a Clinical Instructor, Nursing Instructor or Preceptor). I didn't think this would be an issue because all of the aforementioned have offered to do so. Although I have tried to contact each of these people several times, I can only get ahold of my nursing instructor. She sent one of the two letters that I needed. My clinical instructor is no longer with the school as she has taken a new position and though I have tried to contact her view phone, email and pager, I have had no luck. Same with my preceptor. My previous clinical instructor has offered to write one but can't until this weekend. So...here's my question(s)....

The position starts on Nov 28, do you think this is an acceptable time frame to turn in the second letter? Should I contact the HR person and explain the situation (I have her phone and email information)? Please help. I really need this job!

Btw, the reason I don't have a generic letter of recommendation is because they each wanted to personalize it.