Upgrade to the 77 or 99

It depends on your lenses and how much you want to invest in new ones if you go the A99 route.

If money is no object the A99 will deliver the better results particularly at high ISO but its still no free lunch.

For example if you like to use a standard zoom like the CZ 16-80 or Sony 16-105 on your aps-c cameras there is no modern equivalent available for the A99.  You will have to try and find a second hand Minolta lens for that.  So if the Sony 28-75 or very expensive (and very heavy) CZ 24-70 are not for you, you don't have much choice.

You also lose the crop factor but gain at the wide angle end with the A99.  So if you are into bird photography you get more reach from your lenses on an A77.  An no, cropping the A99 post-processing is no compensation for this either.