"Even the IPCC estimates that there has been a warming influence from the Sun in their radiative forcing summary figure of about 0.25 Watts per meter squared. Adding this 0.25 Watts per meter squared value reduces the percent contribution of CO2 to about 26.5%."
-- What Fraction of Global Warming is Due to the Radiative Forcing of Increased Atmospheric Concentrations of CO2? Professor Roger Pielke Sr., Climate Science
http://www.junkscience.com/

The MSNBC article says "...found that the sun’s brightness varied by only 0.07 percent over 11-year sunspot cycles"

At Earth distance solar energy is about 1400 watts per sq meter, if this energy is varying plus or minus .07 percent then that is is increase or decrease of about 1 watt per sq meter or about 4 times [or 8 times from lowest to highest] of the affect from increase is CO2 content of Earth atmosphere for the last fifty years. This sun brightness variation may be a small affect but the increasing levels of CO2 is a much smaller affect.

A bigger variation from the sun's energy is the changing distance of the Earth from the Sun rather than merely the sun's brightness varying. The mean distance between Earth and the Sun is about 149,600,000 km, but a different between the nearest point and further point is about 6,000,000 km.
"Minimum Distance from Sun: 146 million km
(91 million miles)
Maximum Distance from Sun: 152 million km
(94.5 million miles)"
http://www.windows.ucar.edu/tour/link=/earth/statistics.html

For comparison purpose Venus's mean orbital distance from the sun is 108,200,000 km. At Venus distance the solar energy is about 2700 watts per sq meter or almost twice as much the solar energy per sq meter as at Earth distance And btw Mars mean distance is 227,940,000 km and recieves an average of 600 watts per sq meter- less than 1/2 of earth's.
So the heating affect for this swing in distance of 6 million kilometers, I don't know the exact number [though it could be calculated exactly] but somewhere around a variation of dozens of watts per sq meter.