Some good wrecks up there - try googling for :
Jambo - fairly recent (and not the sad wreck that now is H.M.F.C.
)
Innesjura - nice wooden wreck
Fairview V - fishing boat - small but v pretty dive.
The last 2 are with in a stone's throw of each other. So much so that a couple of year's back we set out to dive the Innesjura but landed on the Fairview - ho, hum
.
In terms of scenic dives - the cliff off the back of Isle Martin is deep and dark
and you can easily blast out to the Summer isles - very pretty scenic dives.
Ullapool Sub Aqua Club Dives has some good info.
In terms of fills - not exactly sure as we take our own compressors;
Air - there is a dive charter out of Camusnagel on Little Loch Broom - they may be able to give fills;
O2 front - no idea I'm afraid. Suggest you ask the local club.
In terms of post dive bits - the Celigdh Place is good for food and the FBI (Ferry Boat Inn) has a good pint.
HTH
Snash