Just had the handle break on a 2001 Sienna. I think the best fix it to just get a metal handle and replace the POS one made by Toyota originally. There is not really that much work, and anybody half handy can do it in about 15min. No need to go to the dealer and pay $$$ hundreds. I picked up a metal handle on ebay for just under $25. Some may want to mess with drilling in the old handle and the screw, but I don't think it's worth the hassle, especially since it's still plastic and can potentially break again. So why do the work twice? All you need is a 10mm socket to undo the 3 screws on the back panel, then pull the cable to release the door, then use 10mm socket again to remove the two nuts holding the holder, then remove the 10mm 1 nut holding the rear plastic piece above the license plate(there is 1 10mm nut on one side and a plastic tack on the other side). Once you remove that, now from outside the car just use phillips screwdriver to remove the two screws holding the handle from the outside. Put on new handle and do everything in reverse. Total time 15min. If you are really slow it may take you up to 1hour, but that is TOPS!!!! Not very complicated at all. Much easier than removing the oxygen sensor on the firewall side of the engine from under the car (that is a lot of fun, ughhh!!!!)
If you have questions just message me and I'll be glad to answer. Have fun doing it yourself and saving $$$ which would go to stealership instead.