Halloween Costumes ideas?

For Halloween my niece Sarah who is 11 years old wants to be either Cruella Deville from 101 Dalmatians or Dorothy from the Wizard of Oz. Her mom, my sister, can't buy a costume for her but will definately try her very best to give Sarah what she wants. Any ideas on how to make little Sarah look like either of these girls? She has dark brown hair and green eyes and is sort of small for her age. She is skinny though and has glasses. She LOVES Halloween!
She wants to be FEMALE

i've been looking for a while and i know that costumes are just starting to sell, but the smallest i can find is for 3-4 year olds. really, i just need the robe and maybe a small enough scarf, and i can draw on the glasses & scar & get a wand from whereever. i thought about getting a larger size and taking it in, but i don't want to pay extra for what i think will probably be a pretty inexpensive costume - when/if i find it. thanks!

http://www.halloweenexpress.com/wizard-wanda-adult-costume-p-7054.html

I'm looking for something to make this halloween costume a little less ordinary. The wand and glasses come with it, so are there any other ideas (leggings, etc.)? Links to actual items would be very helpful....

Thank You!

http://www.halloweenexpress.com/wizard-wanda-adult-costume-p-7054.html

Looking for something that would make this costume a little less boring. It is for parties, so sexy is good... : D The glasses and wand come with it, so anything else would be great. Leggings? Hat? Links to actual items would be awesome.

Thank You!

http://www.halloweenexpress.com/wizard-wanda-adult-costume-p-7054.html

Looking for something that would make this costume a little less boring. It is for parties, so sexy is good... : D The glasses and wand come with it, so anything else would be great. Leggings? Hat? Links to actual items would be awesome.

Thank You!

I am planning to make a Harry Potter costume for a teenager and a Hedwig costume for a 1st grader for the big Harry bash on Friday. I have the robe and black clothes for underneath it for the Harry costume. What should I add to make the costume extra special? How do I get round glasses and a wand?

Also, for Hedwig, I was thinking of gluing a bunch of feathers onto a grocery or trash bag and cutting a hole in the top. Does anyone know a good feather template I can use? Or is there any more ideas to create the ideal owl look?

Also, I don't want to go out and buy glasses and a wand from a costume shop... So don't suggest that please.

I desperately want to make these costumes awesome, and I need some quick, creative thinking to do so. Thanks!