# Choosing location of legend entries in Pgfplots

I am fairly new to using pgfplots and have been combing the manual for a couple hours now and I can't find an elegant solution to my problem. I would like to have two columns of legend entries and then one "label" underneath them all and centered. I managed to get it by playing with the [text width= ] settings, but I was wondering if there was a better way. MWE:

\documentclass[11pt,titlepage]{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.10,
height=0.5\textwidth,
width=0.8\textwidth,
every axis/.append style={thick}}
\begin{document}

\begin{figure}
\centering
\begin{tikzpicture}
\begin{axis}[
legend pos=north west,
legend columns=2,
scaled y ticks = false,
xlabel={Months},
ylabel={Profit},
yticklabel={\\$ \pgfmathprintnumber{\tick} },
ymin={-5500},
xmin={0},
xmax={5.5},
ytick={-5500, 0, 5000, 10000, 15000},
xtick={1,2,...,5},
grid=major,
]