Unfortunately, it is not possible to have a Deathclaw as your main character in Single Player Mode. The only race available for your main character in single player is Human.
You can get the bonus mission by going to the Fallout Tactics download page on this site and downloading the mission from there. The bonus mission occurs fairly early in the game, though, so if you are far along you may have to start a new game in order to get the chance to play it.
The glasses can be found in the building behind the library. There should be a street that runs along the back of the library. Cross the street, and the building here that is closest to the library will contain the glasses.
We are always looking for new questions to add to this FAQ. If you have a question that you feel should appear on this page, please post it on the Fallout Tactics forum. Thanks!