Consultaning Company Non-Compete applicable nation wide

I am a consultant at a Consulting company. After accepting the job they gave me a non-compete to sign which bars me from working for competitors or starting a company in the field which they are doing business. They are a full service consulting firm based in Long Island, NY; providing tax, legal, financial and managerial advisory solutions to religious, nonprofits, public sector & businesses. They currently operate in 25 states. Restriction duration is for 3 years and 300 mile radius from any client they had or currently have or may retain in the future. I have been dismissed because I ask NY law be applied and was told any state law can be applied. Owner does not want to renegeotiate employment package or give consideration or guranteed employment period. So I would be blocked from working in over 50% of the US. The contract was given to me after employment was accepted. I would have had 21 days paid leave, 2 personal days and 6 sick days. Can I be paid for the above? Claim unfair dismissal and unreasonable clause and bring an action for unfair dismissal? What are my options if any. I know it would have not been enforced in NY but he can use a state which would enforce it and file injunction against me in NY. Please advise.