The attorney had to list your note as an asset. Failure to do so could have subjected you and the attorney to criminal prosecution for bankruptcy fraud.
The reason for changing to Chapter 13 is that once the plan is complete, if there is anything left on the note, then you will be able to keep it. If you stay in Chapter 7, you will lose the note entirely.
You really only have the choice of trying to dismiss the case or converting to Chapter 13. Frankly, the cour can refuse to dismiss the Chapter 7 and let the bankruptcy trustee take the note.
If your attorney knew about the note and didn't tell you about that probability, then you may have a lawsuit against your attorney for malpractice. So, you'll have to decide to either go along with the lawyer's advice, or try to find a malpractice lawyer to take your case on contingency.
For a malpractice attorney referral, see: http://www.abanet.org/legalservices/lris/directory/main.cfm?id=MA and www.martindale.com.
Hope this helps.
Terms and Conditions: By your continuing in this conversation with me, or by your clicking “Accept”, you are expressly agreeing to all of the following: (1) our communication is for entertainment purposes only; (2) you are not consulting me in my professional capacity as an attorney; (3) you do not seek to establish an attorney-client relationship with me, nor do I with you; (4) you will not rely on anything I say and you will obtain appropriate legal counsel via a traditional/office consultation with an attorney licensed to practice in the jurisdiction where your legal issue arises (and you may not use our communication to avoid taxpayer penalties imposed by the U.S. Dept. of Treasury); (5) by communicating with me in this public forum you are irrevocably waiving any right to privacy, confidentiality and attorney-client privilege concerning the matters discussed. You further separately declare that any payment made by you is not consideration for this contract, nor offered for any services rendered by me on your behalf, but rather is made in genuine admiration and respect for my desire to help others. If you do not agree with these terms and conditions, then you must advise me immediately.