yes you can buy a policy on the new exchanges and are likely to find a plan at a lower cost - especially if your income qualifies you for a tax credit. starting 1/1/14 insurers are prohibited from denying anyone coverage because of a pre-existing health condition or charging them more for it.
i am retired. i also have a pre-existing condition (diabetes). as a retiree i am offered the option to buy retiree insurance and i currently have that. it is $20 000 a year and climbing 25% per year. i will no longer be able to afford it as my company does not contribute a single penny to this plan. can i switch to the exchange program and/or can i buy my own insurance as an individual now that companies cannot turn me down?