There are several things which cross my mind in reading your question.
First one - you really do need to get insurance in place before getting a diagnosis. It will be extremely difficult to obtain affordable insurance (if not impossible) after diagnosis.
Your choices for insurance depend upon the state in which you live and whether you have access to employer-sponsored group health insurance. If you have access to group insurance, grab it!!!!
Second - you mention that they found lesions. Is that multiple lesions? Lesions which light up with gadolinium constrast? Where were the lesions located and what did the hospital radiologist's report say?
Third - what your MRI report says will affect your current options. What were your symptoms going in?
Fourth - the Multiple Sclerosis Association of America (MSAA) has an MRI diagnostic fund which helps individuals obtain an MRI for assistance in getting a diagnosis or determining disease progression. Information is available here. There is an income limit, as well as other restrictions.
Fifth - I sincerely hope that you do not have MS, but if you do, then you've come to a very informative and supportive place.
Thank you for your question.