Hey looking to add muscle

Hey my name is Joe. I think my goals are different from at least some of you, but I am still hoping I can find help. I work as a fitness trainer at the YMCA in my hometown, but I still don't feel I know nearly as much as I should on the diet side of this. Last year I was 5'10'' and weighed 190 lbs., but it was all fat almost and I didn't feel like my arms were any bigger. See I used to run Cross Country in college on scholarship at Pfeiffer University for two years, and weighed about 155-160 lbs then. This year in May I just graduated from college and decided I wanted to look buff. I decided to try a diet and it hasn't given me the results I want. The last 3-4 months I have gotten a lot of compliments on my muscles (like almost every week), and I think maybe I have added some mass, but not enough to make me happy, I think the compliments are based more on my pump and tone. Like many of you have trouble losing weight, I sometimes think I am a hardgainer, who has trouble adding muscle mass. While I have proven I can get fat (which does give me hope I have the potential to get bigger I need a diet that allows me to put on as much muscle as quickly as possible while minimizing my fat gain). I'd really like to go from 170 lbs. to 200 lbs. while minimizing my fat gain (in other words add 20-25lbs. of muscle and only 5-10 lbs. of fat, because I know when adding mass, you are going to put on fat, it's just really hard not to do, but I want to minimize the fat gain). Does anyone have a good diet plan for a "hardgainer" such as myself (or that's what I consider myself). Besides all this I like trying new restaurants, going to movies, watching college basketball and football (I am an avid NC State fan, especially in basketball, if you get lucky maybe I will take you to a game :P), buying selling sports merchandise on ebay, and of course love working out. I also, like meeting new people and am looking to meet some here. Anyways I'd love to hear from you whether you have information or not, I just want to meet new people. I have a facebook and would love to add you on there. Also, can someone help figure out how to edit my profile picture so my head isn't cut off lol?