My landlord can only raise the rent once a hear based on the percentage increase of the Consumer Price Index. He howeverm, with a new tenant can easily ask for 50% more than I am paying. I have been on a month to month lease for the last six years and for my own security, I would like to enter a one year lease agreement. CAn I insist on a lease agreement for a year or do I have to go the month to month route. I am afraid that if I go month to month, he will ask me to move and give me the requisite 30 day notice.

You can only go on a year lease if the owner is willing. And it has to be in THEIR financial interest to do so. They however have the final decision if they want to renew your lease or not. Or even allow anything longer than a month to month. You can only accept it or leave. That's the benefit of owning the property.

And based on what you are saying... I see no advantage to the landlord to give you a year long lease.

Something sounds not quite right. Where is this, and who set the cap?

Washington, DC. I think if I do not sign a one year lease, he will ask me to move within 60 days and quite frankly, he could easily ask a new tenant to pay $1,800 for the one bedroom I now pay $1.000.00 per month for.

He can raise the rent on a vacant apartment to 'comparable' rent but not more than 30% more than what you paid.
He can raise your rent to 2% more than the CPI per year, but not more than 10%.
I can't find the law that might cover under what circumstances he can force you out just to rent to someone new, but I'm sure it's there if you want to search it. There's tons of legal aid in the area.
DC seems to have pretty well defined rent control and I can't imagine that the landlord can kick you out for this reason. Pay your rent on time and do nothing wrong and find out.
Has he actually said that he wants you to leave, or what prompted this? Is he planning any major renovations?