Interpreting the inverse fourier transform from a graph
If there are no negative frequencies, $x(t)$ would have an imaginary component (see http://en.wikipedia.org/wiki/Analytic_signal), but we can just assume that the graph was truncated for convenience. So I think you have got it right.

Note: previously I wrote in this answer that the coefficients should have been multiples $\frac{1}{2\pi}$ but they are correct if we assume the negative frequencies mirror the positive.