Take the Queensborough (59th Street) Bridge or the Midtown Tunnel to the LIE, to the BQE, to the Grand Central to LGA. Otherwise, if you think it pays, FDR to the Triborough. That's a bit out of the way but it might be faster as there would be fewer lights and it's a straight shot on the GCP. As planeguy727 said, probably 20-30 minutes.
Tho' I've belted you an' flayed you, By the livin' Gawd that made you, You're a better man than I am, Gunga Din!