There is no specific timetable. In fact, the insurance company never has to settle with you. The time usually comes when they want to settle, but not always. And if you bring up the possibility of settlement with the adjuster you will likely lose all credibility and they will "low-ball" you.
Additionally, you have no way of valuing your claim for settlement. It is most certainly in your best interest to retain a Workers' Compensation attorney at this point to evaluate your claim and handle the negotiations on your behalf. You will surely recover more, after the attorney's fee, than you will be able to negotiate on your own.
Please feel free to contact me should you wish to discuss your claim. 985-624-9393.
If you were a Federal Employee when you were injured, you can obtain a lump sum in lieu of periodic payments for impairment to the lower extremities. The OWCP will even encourage you to request a lump sum once you have reahced maximum medical improvement. However, it may not be to the injured worker's advantage because there is a 4% discount, no CPIs and no possibility of time loss during the period when the SA would have been paid.
The issue can be very tricky.I advise you to seek advice from an attorney in your local area or from a union steward. Do not delay.