T.E.
Hi Alissa,
I am a mother of a 13 year old son and 10 year old daughter.
I suggest you create a calendar of (low-cost/no-cost) events with the times and days they are available. I will share the one's I'm aware of to get you started. Sparkles of Gwinnett ( http://www.sparklesrollerrinks.com/index.php?pr=G-Calendar ) has Family Skate Nite Madness on Mondays from 6 to 9 pm where admission is only $1 per/person. Skate rental is $3. And they have a bouncy area for your little girl.
A bi-weekly visit to your library is also a treat for the kids. Check to see when your closest location has storytime for your youngest and allow the older kids to check out books or use the internet.
Purchase a Stone Mountain Park ANNUAL PARKING PASS for $35. You can enjoy laser shows at night, plan picnics, hike, walk, and more for an entire year. (Your hubby and dogs may enjoy many of these options with the family)
Oh my, last but not least, play dates! Yes, meet other parents of your kids friends and enjoy adult conversation while the kids entertain each other.
I'm sure I'll think of more, but hopefully this gives you a
start. Best of luck during the summer.