The cleaners

I have a dilemma and I'd like some advice.  I got a dress to wear for a wedding, but it is dry clean only.  I haven't ever taken anything to the dry cleaners, so I was really nervous to take it in.  I had been talking for a while before taking it in about how I was nervous that they were going to ruin my dress.

Well, we took it in because I had worn it previously and I was going to take it home to Iowa to wear when we went to Circa 21 (which was VERY fun by the way!).  We went to pick it up the day before we left for Iowa, and there were some dark markings all over the dress that looked kind of like grease or something.  I complained about it and was told that it was probably from the cleaning solution and that they would run it again to see if they could get it out.  However, that meant that I didn't get to wear the dress in Iowa since it wouldn't be done in time.  I was bummed, but hopeful that they would be able to get the dirtiness out.

We got a call that the dress was done and that a manager had personally looked it over and it looked good, so now that we are back in CO we went in to pick up the dress.

There are still spots on it.  How in the world did the manager not see them?!

So now we have to wait until Friday until another manager is going to be in so that we can talk with them.  What I want to know is what kind of liability they have to replacing my dress.  I still have the receipt from purchasing it and the original tag.  We didn't have to sign any papers when we brought the dress in to the cleaners agreeing to anything.  The manager originally told us she would reimburse us for the cost to clean the dress and give us store credit, but if she says that again I don't know what to do.  I don't want store credit because I obviously will not be going back to this same store.  I also won't be wearing the dress again if they can't get the stain out...

Thoughts?  Anyone with prior experience in this area?  I hate when my first experience with the cleaners confirms my fear!