2004 SI Hatch Trans problem

[CivicSiHatch]

Alright. I'll try to describe this as best I can. I'm not a car guy by any stretch of the imagination, so forgive any ignorance. Also, go with the back story, I don't want to leave anything out even if it doesn't really matter. For all I know it might.

Car is a 2004 Civic SI hatch. 5 speed, since that's probably pertinent.

Got my tires changed 3 days ago. Discount tire, waited there the whole time. They needed me to move the car into the garage for them, the dude who went out to do it himself tried, and I watched the car jump forward like the guy didn't know how to drive a standard twice. Went out and he told me he couldn't shift it into reverse.

Got in, shifted just fine, parked it on the lift. Full underbody lift that hits the entire undercarriage. Tire change happened, got back in the car and drove off. Everything seemed fine.

The next day my wife told me she had trouble shifting, asked me to check it out. Sure enough, it was shifting wierd. It wouldn't go into first gear while we were moving with any significant speed with the clutch pressed in, and it made a winding noise like gears were rotating fast, no grinding sounds. It would shift into first with a little resistance at under 10mph with that above sound.

The next day, she came home saying she wouldn't drive the car again. Told me that it got stuck and she could not shift it into any gear while on the road. I wtfed, but it shifted for me without any more problem than the day before.

Today, went out to grab some food. Seemed same as yesterday, told her we'd go see a mechanic as soon as we had the money (in about 10 days when financial aid hits, we're broke at the moment) and came home without incident.

Tonight, wanted to go on a cigarette run and the car would not shift into reverse at all. At a standstill with the engine idling trying to shift into first gear made that same winding sound without any grinding. Actually shifting was very difficult, and the car will not shift into reverse. Shifting into first gear made the car attempt to idle forward with the clutch depressed.

Seems like a clutch problem, but I don't know what might be causing it, if there might be a bigger problem, etc. And "seems like a clutch problem" is coming from a guy with only the most basic knowledge of cars gleaned from friends who were more into cars than I ever was.

So talk to me. It's our only vehicle, I'm trying to figure out what I might be in for, what might be wrong in a best and worst case scenario, and what I might be able to do to fix the problem. Cost too, if anyone can help me out with it.

:Edit:

Also, if anyone can tell me what it probably isn't, I'd like to walk into a mechanics forewarned about the possible problems so I don't get "yeah you need a new transmission, it's gonna be a few grand" when (as someone on another forum suggested) it's only a clutch plate and fifty bucks in labor or something similar. Help me not be an idiot or get screwed, I appreciate it.