I just started to read this tonite and wanted to reply but thought it would be too late, however, just did a search and your're obviously still waiting, bugger!
I was in a similar boat to you now, 4 wks ago. My DD is very attached to me and was worried how she would take it all with the new baby and me in hospital. Well, I spent 4 nights in hospital (had a elctv CS) and she would visit with DD everyday and although I talked to her about this well in advance for months actually, the reality was a bit different for her. DH did have a hard time of it, DD pine for me when she left the hospital each day, but really DH just had to deal with it. On the 3rd day I got him to leave DD with me for a couple of hours so he could get a break, and we spent some quality time hanging out, albeit in a hospital, lol. She helped me give bubs her first bath and we read books together and puzzles (make sure you have a armload of her favourite toys/snacks etc in the hospital. I made sure she had a gift from bubs to her and she bought one for bubs too (did that bout a weeks before and took to hospital).
So really the hospital thing was the most traumatising thing for her and she got over it, but she had no ill feelings toward bubs and still doesn't. I'm lucky that bubs is very easy going and sleeps a lot so I have the time to spend special time with her during the day, and DD takes her out to the beach most afternoons/evenings, I have been coming along too lately, which she is happy about.
Basically include her as much as you can, I understand that she's a bit younger than mine but feel your concern. It will all work out as long as she has your time at some stage each day and you and others pay her attention also. I agree with what was said re time in hospital, those 4 nights I didn't stress bout DD or DH, I just bonded with bubs and it was the most special time for us.
Hope all goes well, GL