What are the release dates for Dr- Kildare - 1961 The Visitors 2-3?

The show you're referring to is called "Dr. Kildare", not "Dr-Kildare". There is no episode of Dr. Kildare titled "The Visitors", but there are two episodes with similar titles:

* "The Visitors" (Season 1, Episode 20) - This episode aired on March 29, 1962.

* "The Visitor" (Season 2, Episode 17) - This episode aired on February 27, 1963.

Please note that the first episode is titled "The Visitors" (plural) while the second one is "The Visitor" (singular).