The afternoon heat wave

Our house faces East. We live in a multi-level. The afternoon heat pours into the back side of our house. All of the "important" rooms are on the West side, the master bedroom, kitchen, dining room and family room. I honestly didn't realize that this was going to be an issue until we moved in.

We have since planted trees in the backyard but it will obviously be a while before they start lending the much needed shade. We are currently debating a pergola for shade. I'll add sun shade fabric on top and the side to protect us from the afternoon sun. We looked at metal gazebos but decided against them due to our high wind problem.

I worry about Cassie being exposed to the heat as well. She has her dog house but rarely uses it. I make sure there is plenty of water for her. She loves to sunbathe and be outside. In the heat of the summer, she will just have to stay inside. I'm not sure she'll like it but I don't see any other options.

As for the inside of our house, I have curtains over the sliding glass door and curtains and blinds in the master bedroom. I'm currently researching a way to make my current curtains help with the heat.

As you can tell by the light, the back of my house is fully exposed. Any ideas?