Alex, swallow some pride man, it sucks but just do it. Ask your questions in these forums, the people here are super knowledgeable, and are more than willing to help you. Not everyone is going to tell you something you wanna hear, but what is said comes from knowledge in the hobby.
First thing first. Get some live rock! It is a must and a need. Take your clown back to the store you got him from and get some sort of credit if they will not give you your entire price paid back. The damsel...........if it was me I'd just leave in the tank (store credit would maybe be only 50 cents on a 3 dollar fish). I cycled my 55 gallon years ago with about 6 of them in there, none died, and all went back to my LFS for a store credit. That being said I went with what my LFS said to do in order to get it to cycle. These days there are more humane ways of going about it such as using an uncooked shrimp.
Second, don't get discouraged. You are young and naive and obviously didn't know any better but to take the word of the people at your LFS.
Third, research your thoughts about what you want ot do. There is a wealth of knowledge both here and the rest of the net to help you out. Log on and look it up, and make your decision based on your knowledge from online articles and help from others that know what is best for the enviroment you are trying to achieve.
Lastly, read the different threads on here, even if it is something you are not experiencing at the time. It's still a great way to learn things.