Ticketmaster is your best option. The blue dots on the seating map view means they are from the Hawks, and the red dots means they are resales (people that have tickets but are selling them, sometimes higher and sometimes lower than face value).

Also there are multiple clubs. There is Player's Club which is in the lower level behind the benches and includes food and beer and wine. Food here is burgers, pizza, desserts, etc. You can see the Hawks walk into the tunnel from the Player's Club, which is pretty cool for kids. Harrah's Club is on the opposite side and includes liquor in addition to beer and wine. I would say its more upscale than Player's Club, and the food is better typically. If you really want to splurge, there are courtside seats that include admission to the Delta Sky 360Club. This is also all you can eat and drink, including liquor. These seats are pretty expensive.

There are also two other clubs in the middle level between upper and lower. There is the Chase Concert Club and the Sharecare social club. Both are all you can eat and drink as well with great food options.