You could try the Grand Mer hotel...They have a nice breakfast spread (both Western and Japanese fare), pool, & spa services if you'd like. The only downsides are that there's not much to do nearby and it's in the "love motel" district.

http://daiichihotel-okinawa.com/english.html

You could also try the ANA Manza Beach hotel. It's on the spendier side, but has a solid reputation.

http://www.asiarooms.com/japan/okinawa/manza_beach.html
http://www.anamanza.co.jp/

If you'd like for me to dig a bit more, send a PM!