awk question for a simple regex

I am not a good awk-ward guy

I have a file that has error messages in it.   I do a
head -1  filename |

this gives me the the error message.

I want to PICK the hostname out of the string.

I am in a secure environment so I always use "bart" as an example server name.
Notes: Host:bart Problem:

I want to pull out the part of the string that starts with:  
Notes: Host:

and ends with:
 Problem:

so in this case it would find:
bart