Captain Bruce is a good operator and provides free pick up/drop off service from Hotels in the Waikaki area. They do something that is kind of different as well , they offer introduction to nitrox, where a certified diver can dive nitrox without nitrox certification for only the additional cost of the nitrox tank. They also have 100 cu ft tanks (upon prior request) for more bottom time.
As far as the sites, the ones that we did would probably be a little advanced for a new diver. These included the Sea Tiger wreck (about 115' to the sand) and the corsair wreck (about 110')
We did one dive by an old dainage pipe that was not that spectacular, but we saw an octopus and met a small white tip shark coming out of the end of the pipe.
Some thing that you may want to do is try some shore dives around the island. This time of year, the conditions should be favorable all around the island, so check with local operators for sites and tanks.