You can either:
1) wait for the Department of Revenue to audit you and be subject to the additional tax, penalty and interest on the amount you did owe but did not pay, or
2) you can voluntarily come forward and pay the tax but not be subject to any penalty if you can qualify (and from what you have said so far, you may) as described at http://dor.myflorida.com/dor/forms/2009/gt800053.pdf
"Who is eligible?
Anyone who has any tax liability for a tax administered by the Florida Department of Revenue and who has not been previously contacted by the Department concerning the liability.
Disclosures relating to delinquencies or deficiencies that are obvious and would routinely generate a billing if not otherwise self-disclosed are not eligible for the program."
If, indeed, you were subject to the tax and have failed to pay the tax there is not any option for amnesty for you to not have to pay the tax due.
You should be prepared to determine what was, and was not, subject to sales tax before you submit the Voluntary Disclosure of Tax Liability to the Departmnent of Revenue. Sales tax requirements to collect and pay depend on the particular facts and circumstances of the transactions. For example, Florida sales tax rules can allow you to not collect sales tax so long as you paid all of the sales or use tax on the materials for improvements of residential property.
You should consider using an experienced tax practitioner to assist you with the determination prior to filing for voluntary compliance if you are not able to make the determination for yourself.
I hope this helps you to know there is an option to avoid penalty even though you likely did not want to hear that there is not an option to avoid paying the tax that is due in your circumstances.