How to find out the complement of a language of turing machines?
You cant find the complement of a $TM$ for undecidable languages.
A decidable language is such that a $TM$ which recognizes language membership, always halts with a yes. In this case finding the complement of the machine is simple, just reverse the yes with the no, obtaining the complement of the original decision problem. I leave to you
the task of determining whether the language of your example is decidable or not.

HINT: 
you can compare it with the Halting problem or $ATM$