Keep looking until you get the written short sale approval with the Seller's signature on it and an addendum signed by the seller that says he agrees to all of the terms of the short sale demand letter(s). A lot can go wrong and if you think you will eventually buy this property at the "ficticious" prices (unless it has been previously approved) you may miss other "genuine" opportunities.
To get a better "guess" on how long it may take just for the underlying lender(s) (a Home Equity Line 2nd mortgage adds further complications) to do their independent appraisal of value to determine if your offer is an acceptable price, you will need more information from the listing agent. Also there are some "scams" where the short sale is intentionally delayed so the homeowner can live rent free longer or can collect rents from a tenant longer.
You need a well qualified Realtor to continue to show you properties until you get the approval letter in your hand.... more