Direct replacement of EP1C6Q240C8 in higher family

Sorry, the answer is no.

You may be able to step up to a larger device in the Cyclone family, (to the EP1C12) but you still need to double check that all the pins you are using on the EP1C6 are available on the EP1C12.

If you need a solution soon, I would look at spinning the board with the Cyclone IV device EP4E Family in either the E144 package or U256 package. (Depending on how many IO's you need).

This will be cheaper for the same size device. If you can wait a while. The Cyclone V family will be even lower power and cost per LE, but the smaller family members will be release later. (And are much bigger than the C6 you are currently using.)

Pete