How can one search by area code? the results I get are too far away

You can search by area code there and it works well.

With mobile number portability, etc.

In the advanced search, you can search for your area, such as "United States" & Boston. You can also enter a location in which you are interested (such as Logan if you want Logan airport). I haven't tried it, but TER appears to let you save searches. I'm not sure if it is the query (so that you can repeat it) or the search results.

I would also suggest narrowing you search results a bit (try it without and see how many you get) whether you use physical features or scores for appearance/performance. Start lower than you think and go from their.

Finally, for advanced search, make sure that you set values for (they're at the top of the advanced search page):
   sort by (sorts the results by date of review, appearance, etc)
   show online providers only (obvious)
   exclude bad websites (excludes old and outdated sites)
   exclude bad phone numbers (same)