You have asked several questions, if you have been charged, the statute of limitations would not apply. Also, your prior crimes can affect how you score on the setencing guidelines worksheet. You need to hire an experienced criminal attorney in your area.
The statute of limitations (SOL) varies on the charge. In most felony cases that have a SOL, it runs 3-4 years. In that period, the state must make a diligent effort to serve the arrest warrant and charge. In addition, some circumstances can "toll," or extend, the SOL. Consult with an experienced criminal defense attorney in order to make a determination based upon the actual facts of your specific case as to whether or not the SOL is a viable defense to this charge.
In a case with no evidence other than someone's testimony, the answer is yes, they can convict based on that alone if it determined to be credible. Again, see a lawyer who can evaluate the testimony and attack its credibility.
As for the sentencing, or offer you may have received, your prior history does figure into the guidelines and a judge's decision and so figures into most state offers.
The above is provided for educational purposes only and is not legal advice nor makes you a client of the Mosca Law Firm, PA. Please consult with a lawyer in order to obtain confidential legal advice that is tailored to your specific situation and facts.
When did the alleged act, allegedly occur? If it happened while you were in prison, then you're golden. If it happened after January 2012, then they are well within the statute of limitations period. His word is evidence. It is up to a Jury to determine whether that evidence is enough to prove the case beyond a reasonable doubt. But people are sent to prison all the time based on one eyewitness. It depends on how credible that eyewitness actually is. I offer free consultation if you'd like to discuss this case further.
The answers given by this attorney are for educational and information purposes only and do not constitute legal advice, nor are they intended to create attorney/client relationship. You should seek legal counsel in your area to get legal advice concerning your particular circumstances.