I would just wrap your code in () and use it as a type of derived table and average the counts like this...

select MonthName, Dayname, Average(actualCount)

from

(

SELECT CreationDate,DATENAME(month, CreationDate) as MonthName,DATENAME(dw, CreationDate) as DayName ,count(*) as ActualCount

FROM LogBase

Where CreationDate between @fromDate and @toDate

group by CreationDate, DATENAME(month, CreationDate),DATENAME(dw, CreationDate)

) as a

group by MonthName, Dayname