Yes, Washington Union Station has a Club Acela with an unattended bag storage room for first class passengers.
As for hotels, the Washington region has a lot of hotels. Depending on how much you want to spend and how far you are willing to travel, there's a variety of options.
If you're looking for something a bit cheaper, I'd suggest looking in Downtown Silver Spring (Metro Red Line, 6 stops north of Union Station) or out the other branch of the Red Line (Van Ness, Bethesda, Rockville). You can probably find other cheap hotels in northern Arlington (between Rosslyn and Ballston on the Orange Line) or around Crystal City or Alexandria (Blue and Yellow Lines).
I'd suggest using Hotels.com to get a sense of prices. They even have a map you can use, which has Metro stations on it.