Firstly, do NOT go to the restaurants RIGHT ON Columbus St. in North Beach, they are almost all ghastly tourist traps. North Beach has awesome restaurants, but not on the main strip.
Now to add to the already many great suggestions you have, these are some places to the north of your hotel (i.e. in North Beach).
The House (slightly pricey, also small so need reservation, but truly excellent, esp. seafood, desserts)
Park Tavern (again slightly upscale, but they have really taken off in the last year, and it's very large and open every night I think, so it's easy to get a table -- ask your server for recommendations)
Comstock Saloon or 15 Romolo (these are mainly sit-down bars famous for their cocktails, but they do make excellent small plates if you're hungry but don't want a full meal).
Burgermeister (if you want to be super casual and just have an awesome burger at a very low key place)
Also, generally speaking, there's a lot of good restaurants to the east and south of where you are, but because it's fi-di/ downtown respectively, expect nice places with relatively high prices. Also, in case that's of any interest to you, you are very close to some of SF's finest bars (the ones mentioned above and others).