you need a supplemental and you need to begin working on it now. I have Continental Ins and it's a good one. I have Plan C with Medicare, the one that, I think, takes care of deductibles. My supplemental picks up where Medicare leaves off. There are bunches of plans with Medicare so you need to look at them carefully. Call Medicare and ask for a booklet that shows you all the plans that Medicare has (this may be in what Ross posted above). Look carefully at them all, choose the one best suited for your husband and then talk with an insurance co for the supplemental and tell them which Medicare plan you will be getting and they can advise you about what they offer. If your husband needs any extensive, expensive care, you would have a big bill left after Medicare pays its 80% of covered charges. Not all charges are covered by Medicare and each year there are fewer benefits, but all in all, it's good and so many of us would be devastated - and dead - without it.
Next year the drug benefit will be coming out, but none of us know just what it will be yet.
You must get your supplemental by the time your husband is 65 because there's an enrollment period you must meet. If you don't get it by his 65th birthday, you may have to wait for the next enrollment. It's pretty complicated.
Then write down your findings so you'll have them at your fingertips.