Hi, Jenny!
Guests can find times for many of their favorite shows by visiting Walt Disney World's website, and
Disney Junior-Live on Stage! is no exception.
Once you're on the page, take a look at the times listed to the right. Click on the calendar icon, and you can then select the date you'd like to investigate. For example, on 5/9/13, the shows are listed as 9:40 AM, 10:30 AM, 11:20 AM, 12:10 AM, 1:30 PM, 2:20 PM, 3:20 PM, 4:10 PM, 5:00 PM AND 5:50 PM. The times for the next day are the same as well. Your daughter is going to LOVE it!
If you are heading to Disney's Hollywood Studios from Epcot, I suggest that you exit Epcot from the "back door" entrance at International Gateway. When you are in World Showcase, standing at the end of the bridge that connects United Kingdom Pavilion to France Pavilion (with UK directly behind you), there is a wide walkway that slopes right down to Epcot's other entrance: International Gateway. Just past the gate you'll see a Friendship boat, which will take you HS. However, there is a great, lighted, easy walkway that follows the water from Epcot to HS, so if your little one is in a stroller and you like to walk, you can be at Disney's Hollywood Studios entrance in about 10 minutes by foot.
Regarding which day to go, both days are predicted to be about a 4 on a scale of 1-10 for crowd levels, according to the unofficial site touringplans.com, so either one should be great! However, if this is a must-do, I suggest that you plan for the earlier day. If something happens to prevent you from getting to the show, you'll still have a second opportunity to see it the next day.
Send more questions as you plan this great trip, Jenny! Can't wait for you to experience the magic of WDW in person!