Yes, the of 6570 would be the equiv in terms of spec., but a quick search finds the Acer 7750G with a screen res of 1600 x 900 (although there was one result going on about a 1080P version).
Now 1600x900 = 1,440,000 while 1080P (1920x1080) = 2073600 which is almost x1.5 the amount of pixels. So yes, a 6570 is equal to your 7690M but the gameplay and performance would not be equal if the desktop were to run at a higher resolution like 1080P. (And that's why the sticky in VC&G asks for screen resolution otherwise it's hard to make recommendations.)