STYLETHREAD -- LET'S TALK SHOP!

I will try to keep this short, but I have a feeling it will get long in a hurry.

I want to get into HR. A position opened up at my company in that department, however, the position isn't exactly what I want, plus it is part time (I'm full time now).

I can not afford to work part time.

All HR positions I am interested in outside the company require a few years of HR experience, which is the only reason why I am considering this job. (Oh, and to just change jobs in general, as my current position may very well be making me crazy).

The kicker here is that my current job could be done by a part timer. I am busy about a quarter of the time I am at work. Further, the HR department is short staffed right now, and I am surprised that the job posting is only for a part timer.

So, I need to suggest to them that they could hire me into the position full time, give me more responsibilities than the job posting suggests, and then make my current position part time. That way the budgeted time for the company is a wash, and I can still pay my bills.

Do I wait for them to offer me the job before I tell them I have this plan, and oh, by the way, if you can't/won't do it my way I cannot take the job?

Do I mention it in the interview?

Do I assume that they will ask me why I want to go part time, and then drop my idea on them?

Keep in mind I am in Michigan, and the job market couldn't be crappier. The idea of suggesting to the company, which is in a depressed industry,  that my job could be done by a part timer is scary. What if I didn't get the HR job, and then they decided to make my job part time any way? I'd be SCREWED! Is that just a chance I have to take in order to hopefully get what I want?

Any insight is greatly appreciated.

TIA

-gd