Hello and
to Purrs.
It's very sad, but JaneyK has given you great advice I thought I'd top up with some handy tips to get you through until she is re-homed in relation to allergies.
I've tried numerous things here, and will only mention those that have worked best for me -
starting with our best defence which is
the Dyson Pet vacuum cleaner with HEPA filter - utterly brilliant, don't forget to wash the filer though.
Then the Pets at Home anti-allergen wipes - wipe the pet daily and your hands after handling her and the effects of the dander are very much reduced.
http://www.petsathome.com/shop/allergy-relief-pet-wipes-15-pack-by-petkin-%28online-only%29-105201Introduce anti-allergic cleaning fluid range Petal Cleanse into your everyday life. Use this to wipe down surfaces close to the baby as well as on your skin and wiping down the cat with damped tissue. Separate formulas for each task but very effective! I bought the PaH wipes (above) then re-use them refreshed with a spritz of PetalCleanse
http://www.amazon.co.uk/Bio-Life-Cleanse-Anti-Allergen-Furnishings-Fabrics/dp/B003MA1VU8/ref=sr_1_5?ie=UTF8&qid=1353510208&sr=8-5I recommended this lot to my neighbour whose son was allergic to their cat and his allergies have now vanished completely. They managed to keep their cat in the end.
This might seem too obvious, sorry but if your cat is tending to sleep in the child's bed it might be worth investing in a door spring to ensure the baby's bedroom door stays closed at all times.