Zoo's for the most part are mod to high light corals. Only certain mushrooms like low light as a lot also like mod to high light. The watts per gal
rule is very vague and should not relied on. A better way is tank depth, coral height etc. Right now you may be able to keep a blue, green, or giant mushroom if you put it high in the tank. A sun polyp is a coral you can keep but will take some additional care/feeding compared to mushrooms. If a light upgrade is possible I would suggest it if you are wanting to try corals. If you buy one coral then you will eventually want 2,3,4
If you do the upgrade you will be able to keep additional moderate light corals. Liveaquaria.com gives you a good idea of corals requirements.