After 13 months together you should know by now what his favourite meal is.
As for what to wear, that would depend on a lot of things. Not least, how old you are, and what you want from the night, if you know what I mean.
Really, you should know what to do much more than anyone else would. This thread is rather pointless because most suggestions won't be suitable for your relationship. If you aren't going to come up with your own ideas for the night, then it won't be your ideas making the night special for him, it'll be someone else's ideas.
Best possible suggestion: be yourself. That's who your boyfriend wants you to be.