First and foremost, you would be best served to meet with a qualified employment attorney without delay.
As my colleague noted, the practice of law is a business. In that regard, the issue most folks have with a circumstance of this sort is not finding a qualified lawyer that will take their case, but, more correctly stated, finding a qualified lawyer who will take their case on a contingency fee ("no recovery, no fee") basis. If you have the money to pay for your representation, then you will, almost certainly, find many attorneys that will "take your case".
With that said, the question of how long you have to file a lawsuit may be a bit more complicated than it appears. You may, for example, potentially have claims under Florida law (in addition to federal law) that typically have a different filing deadline. Moreover, you may have claims other than those involving discrimination that would also generally have a different filing deadline. A qualified employment attorney can address these issues with you.
Finally, while you can certainly file your own lawsuit, successfully handling your own discrimination suit would be extremely difficult for most non-lawyers.
You are asking all of the right questions, and you have done what you needed to do so far. The law is simple on this point, even if it is a little unfair. You get 90 days from your RECEIPT of the Right to Sue Letter. Generally, the law adds 3 days from the date of mailing to come up with the date of receipt. To eliminate that issue, most attorneys who are serious about filing winning claims will make sure they file within 90 days from the date of the mailing of the Right to Sue letter. If, however, you don't find an attorney who wants your case, then you cannot get an extension. You file it yourself (NEVER a good idea) or you lose it. I often deliver the bad news up front to people who contact me: if I don't want the case, it's because it is not a good one. No one wants to hear that. But in the end, lawyers are trying to make a living, and if they think they can win a case based upon the facts, the law, the attorney's area of practice, etc., they will take the case.
As attorney Sanford stated, the 90 days is calculated from the date you receive the right to sue. If you do not file your lawsuit within those 90 days, you forever lose your right to sue based on the issues in your underlying charge of discrimination. If you don't find an attorney until after the expiration of the 90 day period, your claims will be time barred.
I don't know how far into the 90 day period you are, but keep looking. Try Avvo, National Employment Lawyers Association, and the Florida National Employment Lawyers Association (links is provided below). Good luck.
The short answer is that if no lawsuit is filed after 90 days from your RECEIPT of the Right to Sue Letter, your claims are forever barred and you will not be able to recover anything. Employment cases such as these are rarely simple and are best handled by an employment attorney. You can try to file something for yourself but your odds of successful recovery are greatly diminished by doing so. If you truly cannot locate an attorney, you will need to draft a Complaint and file it with the Court (either state or federal). As a sustaining member of the National Employment Lawyers Association (NELA), I can tell you that there are many members here in the State of Florida that assist people just like yourself- NELA operates an attorney locator to assist in finding an attorney. Go to www.nela.org for more information. Best of luck!
Feel free to contact me directly for further information at 239-985-9691 or to speak confidentially- the information provided herein is for general information only and does not constitute legal advice, nor does this communication in any way establish an attorney-client relationship.