C.K.
I have the same problem in our bedroom. I tried the foil in the window, mini blinds, blankets, dark screens and none of that worked. What finally worked for us is 4 layers on each window in the room. Closest to the window is a paper black-out shade, then a vinyl roll down shade, then a black-out energy efficient (or solar) curtain, and all of that is covered with the decorative curtains that match our room.
Our room is very dark, but it is also much cooler. The stuff that I bought is inexpensive and works wonderfully. Before the 4 layers on our window the coolest I could get our room was in the high 80s, now our bedroom is 72 - 75 degrees at the hottest time of the day. Once the sun goes down we can get the temperature in the 60s if we want it that cool.
*Edit to add that my windows are very old, single pane windows.
None of the stuff I bought was expensive. It all came from walmart, but here are links to Home Depot showing the things I bought. All of it comes in different colors and sizes.
Paper Black-out shades
http://www.homedepot.com/Decor-Blinds-Window-Treatments-B...
Vinyl roll down shades
http://www.homedepot.com/Decor-Blinds-Window-Treatments-B...
Energy efficient curtains or solar curtains:
tp://www.walmart.com/ip/Eclipse-Samara-Blackout-Energy-Efficie...