If you want EAN in RI you basically have two choices, Newport Dive Center or Narragansett Pier Dive Shop.
As for water temps, RI is pretty warm in August. Expect upper 60s unless you go really deep. With a name like "ArcticDiver" my guess is that you can handle that without a drysuit!
If you go to Massachusetts and dive on the north side of Cape Cod the water is typically in the mid 40s to low 50s at depth.
For charters your choices are very limited in RI although one of the boats is pretty famous. The famous one is the Seeker (the boat from the book Shadow Divers) over in Newport. The other option is one boats that works with Narragansett Pier Dive Shop out of Pt Judith. The trick is going to be whether you can find a mid-week charter while you are here.
As for sites, the wreck of the U-853 is the most famous one. It is in 130 ft of water with the deck at 110 so it is an advanced dive. If you do a Google search you'll find a ton of info on it. There are also a lot of other wrecks, many of which are shallower.
RI has tons of great shore diving. We have some nice rocky coastlines that make for some nice scenery. There are also several deep walls accessible from the shore that are covered with anemones. There are too many sites to list, but most of the coolest sites are in Jamestown, RI. I am sure if you fish on this forum in August you can probably find some local RI diver willing to show you some of the good local shore dives.
One cool thing that happens during August is that we get stray tropical fish coming into the area. They mostly hang out in the shallows along the coast, so unless you do shore dives you'll probably miss them.
