How long should I stay at this job?

My job right now is a retail manager/ wine buyer. The work is challenging and engaging, and I want to build a career in the wine industry. I was hired to work Tuesday- Saturday, nights, which is pretty normal for retail management.

Six months in I got stuck with a six-day work week. The local liquor laws changed so that we could be open on Sundays, and I ended up with the Sunday shift. The staff is tiny, and the other manager also works six days, so there’s nobody else right now who can do it. (We have two part-timers who are college students, and one full-time employee who doesn’t speak much English. Still, I’m working on training.)

I’ve been here a year and a half. There’s a HUGE development being built near us, which will be done in a year. Once it’s finished, we’re expecting a big influx of customers. My boss says he’ll consider creating a 3rd key position once business picks up in a year.

I dropped out of college and worked all sorts of crappy customer service jobs before ending up here. This is the first position of real responsibility I’ve had in the wine business. It’s important for me to do well here because it will be the cornerstone of my resumé for the next few years.

A lot of people in my position go on to work for wholesalers or importers, where they build great careers. It seems like a great next step for me. You don’t need a college degree, just wine knowledge and several years of experience.

My original plan was to stay here several years and then look for a job like that. But the six-day week is really messing up my quality of life. It would be ok if one of those days were a weekend, or if I worked days sometimes, because then I could at least see friends and family. And I don’t actually know if I can go back to a five-day work week in a year.

OTOH, professional wine jobs are hard to find. Most of my previous jobs have only been for a year or two. If I leave now it will look like I’m job hopping, and I’ll probably have to make a lateral move instead of the step forward I’m hoping for.

So, what should I do? I’ve been on the lookout for jobs for the last few months, but I’m also trying to make the best of the current one. Should I tough it out for at least another year? (I could, and I don’t mind paying my dues and working hard to get ahead. But this seems a little beyond that.) If not, how soon can I leave without hurting my career chances?