You can use
keywords=[<number>]{<list of keywords>}
to add another set of keywords and then
keywordstyle={[<number>]<style commands>},
to give a style for this new set.
Since I didn't have the original definitions for your colors nor of the \ttb command, in the example below I used some own settings, but you can easily use your own settings; the code was randomly taken, just for this example.
\documentclass{article}
\usepackage{xcolor}
\usepackage{listings}
\usepackage{bera}% optional; just for the example
\lstset{
language=Python,
basicstyle=\ttfamily,
otherkeywords={self},
keywordstyle=\ttfamily\color{blue!90!black},
keywords=[2]{True,False},
keywords=[3]{ttk},
keywordstyle={[2]\ttfamily\color{yellow!80!orange}},
keywordstyle={[3]\ttfamily\color{red!80!orange}},
emph={MyClass,__init__},
emphstyle=\ttfamily\color{red!80!black},
stringstyle=\color{green!80!black},
showstringspaces=false
}
\begin{document}
\begin{lstlisting}
def under_attack(col, queens):
left = right = col
for r, c in reversed(queens):
left, right = left - 1, right + 1
if c in (left, col, right):
return True
return False
print 'This generation has {0} babies'.format(babies)
ttk.Button(buttonframe,width = 3,
textvariable=guivars["%s %s" %(current, item)],
command=lambda: remoteButton(current, item))
\end{lstlisting}
\end{document}

Please notice that "ttk" is being treated as a keyword with red color, as was also requested.