Good Morning wendyj,
The TM has mentioned that the castle complex is not included in the tour but you should still have time to do this.
There will be a 40 minutes break in the tour of the city for drinks. At 09:15, you will be with a local guide for a half day of sightseeing in the included Prague Old Town visit. Following this, there will be an optional boat cruise along the Vltava River. You will then have free time up until 15:30 when you will meet at the coach and return to the hotel.
Kindest Regards,
Amy