Need some song ideas for a charity concert?

I'm going to be singing at a charity concert in my local shopping
centre in just under two weeks, and I really need some ideas for
picking some songs to perform. Personally, I prefer to sing songs from
musicals (from Les Miserables, Miss Saigon, Wicked, etc) however, I've
been told to try and sing mostly more modern, well known songs. I was
thinking along the lines of Adele, Kelly Clarkson, etc, though I'd
really appreciate some other ideas. I need to choose about twelve
songs all together.

So far I've selected;
1. Duet of 'A Thousand Miles' - Vanessa Carlton
2. Rolling in the Deep - Adele
3. Defying Gravity - Wicked/Kerry Ellis
4. Duet of 'What is this Feeling?' - Wicked
5. Turning Tables - Adele

Any ideas would be appreciated! Thank you :)