I'd be curious to know why it was listed first as a three bedroom. In my state there are strict rules regarding listing a home as a bedroom. If it does not have a closet, it cannot be counted. However, the opinion changes from agent to agent as to what constitutes a closet. It could be a free-standing closet or a half closet or a closet just outside the door that only serves that room.
It is also not unusual for the listing agent now to have shown the home. Most showings are done by the buyer's agent bringing the buyer. Unless someone specifically calls your agent and is not represented by another agent, she would have no one to show your home to.
As for listing as vacant when in fact it was not, that would worry me some. Sometimes, if we are listing a property in the weee hours of the night, we are tired and one click of the mouse can create an error. It is for this reason that I always ask my seller to look over the listing just in case! Apparently, you didn't notice these discrepancies. I do not mean to imply that it is your job to do so..... just curious.
Regarding the short sale, there ARE many good reasons not to list as a short sale if there is no urgency to do so. The best one I can think of is that buyers wouldn't even consider a short sale up to now because there was an almost certainty that they would not get accepted and/or closed in time for the tax credit. Now that the credit is almost up, the short sales should see an increase in activity.
Unless your agent is the one bringing the buyer, I doubt that she is getting 6%. That listing commission is usually split between the buyer and seller's agent and often times the banks holding the mortgage will ask for that to be reduced as well, so it's possible she is anticipating that.
As uncomfortable as it may be, I think you owe it to yourself and your agent to sit down and calmly discuss the issues you have presented. If she is not willing to do that, then it's time to go to her broker!
Have you considered renting it out?
Vacant when it is occupied is also a big mistake. What I would consider doing, since you have other issues you would like to have addressed and answered is talking with the agent and her Broker at the same meeting. Calmly ask what happened and you would like a win win situation with the result of selling this home quickly. Most agents do not receive 6% unless they sell the home themselves and don't have to split it. Otherwise 3% goes to the listing agent and 3% goes to the selling agent.
You need to price your house correctly and if you do not have the funds to bring to closing then you may have to do a short sale. Sounds like you may be overpriced if you have not gotten many showings. Normally the listing agent does not find the buyer. Buyers are already working with agents and when a new listing comes up on the computer that fits their buyer's criteria they take them to see the house and if the house is nice and clean (clean enough to eat off of the floors and no pet or smoke odors) and uncluttered with "grandma" style furnishings and wallpaper, freshly painted both inside and out and priced correctly then they make an offer. If any of those variables are off the house may ultimately sell for a lot less.
Does the 4th bedroom have a closet? If not, then it is truly NOT a 4 bedroom. If it doesn't have a closet, buy a small cheap one at IKEA and install it on the wall with screws to make it a "bedroom".
Your agent will split the 6% with the buyer's agent and if she is foolish to work with a larger Real Estate firm that keeps half of her commission then she'l only get 1.5%. If you have a $500k house then it may be worth it to her to give up 1%. If you have a $200k or less house then you shouldn't even ask,
If worse comes to worse, you can move and continue to market the home from where you locate - if the broker has not taken the steps to correct the situation, you may want to interview and list with another broker as well. Do make certain the next time - that the broker will do more than just list your home in the MLS and allow others to show it. You're the boss!