I know it won't help much but I'm sure that Kyra will be fine and once she is settled you will enjoy that couple of hours to yourself as well. I work in a pre-school and have seen children that have been used to being left taking time to settle and those that have never been left (only gone to toddler groups) settle with no problem at all.
Have you been for your visit yet to the pre-school? If not then check their settling in policy, any pre-school worth their weight in gold will have an 'open house' policy and should welcome you with open arms to stay around and settle Kyra for as long as it takes, we've had parents staying for part of sessions for almost 4 weeks, sometimes going for a walk for 10 - 15 minutes and then returning, building up that trust that 'mummy WILL come back' at the end of the day it's the child's happiness that is the most important thing.