According to the info in this link, unless you have any children that are not his or he has any that are not yours, you are entitled to his entire estate:
To protect your interests, you should follow the procedure for opening probate in the appropriate county (where he was living). If your husband's estate is insolvent, it will have to go through formal probate. This website has a probably trustworthy explanation of how it all works, even if it isn't your county: http://www.mncourts.gov/district/2/?page=768
You'll have to pick someone to propose as the administrator of the estate. You could probably propose yourself, but if the estate is complicated (whether by having a lot of assets or by having a lot of debts) you might find yourself overwhelmed by the job. Not sure to what extent you can have yourself appointed and then delegate the actual work to a lawyer you hire. If you can do that, it would make it easier to hire a different lawyer if you find you're not happy with your first choice (easier than it would be if the lawyer is the one appointed as administrator).