You only need to collect one more medallion and save the final sage before the battle with Ganondorf. The Spirit Temple is one of the easier temples to complete as long as you can complete a few intricate puzzles. Good Luck!

Near the entrance to Gerudo's Fortress lies the entrance to the Haunted Wasteland. Climb the ladder beside the gate and speak to the Gerudo up there. She will raise the gate for you, allowing you to cross the Desert. Climb down and head into the Haunted Wasteland. As soon as you enter, you'll find that the raging winds and blowing sand makes it very hard to see. Stand on the crate just ahead and use your Longshot to pull yourself over by targeting one of the three crates on the other side of the River of Sand. If you attempt to walk over the River of Sand, you'll be sucked down into it and brought back to the beginning of the wasteland. Once across, you will see flags which mark the proper path. Follow them one-by-one and when you see a sign that says something about a Desert Merchant, ignore it or you'll be ripped off. Don't try to skip a flag or you'll be brought back to the beginning. Soon, you'll arrive at a small structure surrounded by flags. Before going up on top, head inside and you'll find a Gold Skulltula and two unlit torches. Kill the Skulltula and get the token. Stand between the two torches and use Din's Fire to light them. This should make a small chest fall. Open it to claim fifty rupees! Climb out using the ladder and go up on top of the structure. Read the writing on a stone there and it says something about "One with the Eye of Truth" This is a complete giveaway for a hint! Use the Lens of Truth to see a hidden ghost in front of you. Follow the ghost and it will lead you to the Desert Colossus. It may seem that the ghost is bringing you in circles but its not. You'll arrive at the Desert Colossus if you follow it. Don't lose sight of him or you'll have to start over. When you see two flags beside one another, keep running towards them because that's your destination!