If you haven't signed a contract with your agent, you are probably free to move on. If you have signed a representation contract, or if you have made an offer on a home, you may be obligated. As Dp2 correctly pointed out, your first option is to discuss with your agent why you are not happy. If you don't get satisfaction, talk with your agent's Broker.
Dealing with the Listing Agent works against your interest. The Listing agent's job is to get as much money as possible for the home. They represent the interests of the Seller, not you. You agent's job is to get you exactly what you want, and negotiate the best price and terms for you, then manage the details. Your agent should be a trusted advocate on your side.
Most of the time, when a client is not happy, it's because they don't understand how complex a Short Sale can be and the level of detail that is required. The Buyer thinks nothing is happening and can't understand what is taking so long.
You might find this recent blog posting of interest: http://www.trulia.com/blog/ellen_doc_stephens_realtors/2010/
By the way, when we run into an agent who "hints" that they can help you, you can be sure that the primary interest of that agent is neither that of the Seller or Buyer, but their own commission. It is impossible to represent both sides in a gun fight. Agents who take both sides, unless it is clearly understood by all that the agent is strictly enabling the transaction and will not be providing advice or opinions to either side, run the great risk of conflict of interest with both sides. Suggesting that the Seller might take less is flat ILLEGAL in most states, and a clear breach of ethics. "Hint, hint, wink, wink" are more suited for the used car lot than the Real Estate office.