You might want to post an inquiry on the Boston board of
www.chowhound.com. If you post using the same handle, I can help guide you through which responders I trust.
For traditional New England-style seafood, you are walking distance from a branch of Legal Seafoods. There's nothing cutting edge about this place, and many Bostonians are jaded about the place, but it's still a good place for reliable, solid, traditional seafood. There also is a seafood restaurant, Turner Fisheries, in the Westin, across the street from your hotel. The menu is perhaps a little more creative than Legal's, but I think the food at Legal's is better. Expect to spend around $50 p/p at either.
My favorite seafood restaurant in the area, and one of my favorite overall restaurants in the area, is East Coast Grill in Cambridge (an easy cabride from your hotel). It's not traditional New England seafood, but it's a lively place with great food and strong flavors, with an emphasis on seafood and barbecue. Check out their website:
www.eastcoastgrill.net.
Another fabulous seafood restaurant, not far from your hotel, is B&G Oysters (also one of my favorite Boston restaurants). The place is styled as an upscale casual rawbar, but it is run by one of Boston's best chefs, which really shows in their food and service. The menu leans toward the traditional, but the preparations are wonderful and the food truly is exceptional. It's a little pricey, so check out their menu to see if it fits in your budget:
www.bandgoysters.com.