Which available method should I use to pay for this class I'm taking?

Ok, long story short…. I’m attempting to get a job in the Forensic Science field (most likely as a Crime Scene Tech/investigator, or a Crime Lab Tech.). I am qualified for the position based on my education, or at least I’ve been qualified for probably 6–7 of those I’ve applied for (so much so that my resume at least reached the consideration step). Anyways, last week I took a test for a position with Grand Rapids Michigan’s crime lab. Basically it was a test on the field (again, Forensics) to make sure you have the know how. If you scored 70% or higher on the test you then take an oral test with the lab managers, and then they take the best applicant from the pol they’ve built. I literally had no clue what was going to be on this test, and the best hints I could get from their HR person weren’t very helpful. Through studying what I could find on forensics, I still managed to pull a 69%, but that wasn’t enough to move on.

In an effort to better prepare myself for these “entrance” tests (which several of the jobs I’m looking at have), I found a class at the local community college. It’s an intro to Forensics class, it’s brand new, and the guy who teaches the program at the main state school locally (Ohio State) teaches it there as well.

The problem is the cost. It’s roughly $550 including books. I don’t have a major savings to pull from other than a stock account, but I would take a huge loss if I sold my stocks now to raise the money. My three available options are as follows:

1) I could put the tuition and book costs on my credit card. It is a zero % interest card at the moment (and will be til November). I did an intro rate card with the goal of paying it down by then, or swapping it to a new 0% interest card in November. As such I’ve been paying a bunch of extra money into it every month. The tuition costs would wipe out at least one months of payments (I’ve been putting ~$400/month into it), putting me that much further behind there… but it would pay for the tuition.

2) I could take a loan from my 401k. Now before people jump on me, this is not a withdrawal from my 401k. Basically it would be me “selling” my shares of the 401k fund (not all of my shares, enough to get the money needed) to the bank, and then me buying back as many shares as the money they pay me will. So if I sold $100 worth of shares, I would buy back $100 worth of shares (+interest) over the course of the loan. This can hurt my 401k in that the money I “borrow” from it is not exposed to the market, and cannot accrue market interest. It can also help the 401k, because if the market goes down, I still make the interest I pay on the loan (that interest goes to me, not the bank), and I don’t lose any money from the stock devaluing (not to mention I buy back more stocks because they cost less so my original $100 buys more of them). If I do that option I can choose exactly how long I want the term of the loan to be, be it 2 months or 50 years.

3) My g/f has offered to loan me the money. We are moving in together and we’re rather close, but I don’t feel very comfortable borrowing that much money from her. Not to mention it would take me some time to pay her back in full. What if things sour in our relationship or if she suddenly/desperately needs her money?

What do you guys think?