Sound difficult... I only have one daughter 6, barely 6 months old, but from what i know (and try) with her - baby steps...
You put her down and sit next to her, you can comfort her - on the floor or by holding her, but then put her down and try gradually to comfort on the floor and after it works - try moving further from her - always talk to her.
Then (hopefully) you'll be able to go to the kitchen - still talk to her from there - then your room, and still talk to her. Your voice should be your normal voice, in order not to make her think there's a real reason for being upset (i made this mistake once - when she cried i held her in front of me and said "mummy's here, mummy's here" with horror in my eyes and complete panic - it made her histerical of course).
I think it should be a process - first hold her, then try putting her on the floor still holding her and hugging her, then just sit with her and touch her, then just sit, then move further. Good luck!