Just express that you are very interested in the job

Agree, do not play sympathy card.

I am interviewing candidates now. I can image if the applicant "begs" me, I will be truely embarassed and feel very uneasy. I will feel bad either way:

1) to unaccept you on this ground----not fair for our candidates, who might happen to be in the same situation as you and also if they are more qualified. Plus, it is not a good way to start a supervior/employee relationship, this information is just too intimate, too personal

2) not to accept you: feel bad that I turned down a person who counts on me/job

3) however, express your real interest in the job is never wrong. You will be hired I feel just on your qualification.

4) Good luck. Just my two cents