It will be at least 7 aricraft at Liverpool for next year, maybe 8.
I'm not sure it will be. Liverpool had only 6 for summer 2012 and in the recent expansion announcement for 2013 by Ryanair, it doesn't say they will add another aircraft to Liverpool whilst saying East Midlands and Manchester will both get another one.
Since 2012 was:
EMA - 6
LPL - 6
MAN - 4
Then that would surely mean for 2013:
EMA - 7
LPL - 6
MAN - 5
You may just get more flights with aircraft not based in Liverpool. Also, since Liverpool has a lot of short flights to Ireland, aircraft can do more rotations in one day so they could still do it with only 6 even after the new Lublin and Zadar routes commence.