$$\int_0^x \mathrm{Q}(t) \, \mathrm{dt}=\frac{1}{2}\int_0^x \mathrm{erfc} \left( \frac{t}{\sqrt{2}} \right) \, \mathrm{dt}=\frac{1}{2} x \, \mathrm{erfc} \left(\frac{x}{\sqrt{2}}\right)+\frac{1}{\sqrt{2 \pi}}\left(1-e^{-x^2/2}\right)= x \, \mathrm{Q} \left( x \right)+\frac{1}{\sqrt{2 \pi}}\left(1-e^{-x^2/2}\right)$$
which can be shown by integration by parts
your integral can then be found by change of variable