There are a lot of things that you can keep under lower levels of light, including SPS corals. It may not be realistic, however, to expect the same kinds of growth rates or colouring that you would see under higher levels of light. I've personally kept SPS corals under normal output fluorescents (some encrusting montipora, and some small frags of plating montipora). While the frags were brown the whole time I had them, they grew, albeit very slowly. I wouldn't want to try higher light SPS corals like A. humilus or A. cervicornus under anything other than MH though. Those types of corals enjoy being absolutely blasted by the sun since they are normally found on the crest of a reef.
Something else you may want to consider is the amount of nuissance algae that may begin to appear if you upgrade your lighting. Lighting doesn't specifically cause algae, but it can tip the scales in favour of algae growth if the nutrients are there to begin with. Many people report rampant algae growth when switching to brighter lights, especially when the tank is young and the water chemistry may be unstable.
If you're happy with your tank, stick with what you've got. It sounds like things are going well at this point anyway. If you leave the anemone alone for the time being (they depend on other things besides light, like tank stability), you should do fine.
