Relactation is more than possible! Congradulations on wanting to give it a try again. Now for the advice...
Since you mentioned your little one has allergies, I suggest you cut all dairy out of your diet and don't sub soy, sub rice milk or other (it takes 2 wks for it to fully be gone, but don't wait to start bf she'll probably be fine). I've been dairy free for 2 years b/c of Douglas's stomache problems.
You may need to purchase a SNS (supplemental nurser system). Your little one will get the immediate satisfaction which is what she is now use to from the bottle and you get the nipple simulation that you need to bring your milk back up to a full supply. With my first I tried to alternate between bf and bottle feeding during the same feeding, it didn't work, I wish I'd had an SNS. I did not successfully bf my first b/c of bad information and lack of support.
The best piece of information I ever got (from an IBCLC when I was pregnant with #2)) was that a woman has multiple "let-downs" that can be 5 - 7 minutes apart. I waited almost 20 minutes with my little Douglas for a let down, he was wimpering and crying and I just latched him back on again and again. I stroked his little head and said, "suck baby it will come". I didn't alternate breast the way I should have b/c I thought it would be better to stimulate each breast a little instead of a lot. I wish I had followed the nurse on the side you last nursed on, first with the next feeding; I have been doing this with Amelia and she is so filled out!
The above method of just continuing to latch the baby on (w/o a SNS is the cheapest, but the most frustrating).
Finding a good lactation consultant is sometimes very difficult. If your local hospital has bf services, they may do free consults (ours does). If you have about $150 and insurance which you can fight for the reimbursement, find a IBCLC in private practice.
A La Leche League meeting or call to a local leader is a good place to go for support, but as far as good advice on relactation, I was steared the wrong way.
Read, Read, Read... The best thing you can do is educate yourself on how your breast work. Be sure that your sources are pro-bf ; LLL has good publications The Womanly Art of Breastfeeding, everytime I read it I get something new from it and Dr. Sears Breastfeeding Book. The library can be a great resource for free reading.
Reglan is a prescription drug that is prescribed for lactation when a woman has stopped, but it is most successful if used before 12wks (from The Nursing Mother's Companion 3rd revised Ed. pg 81 - 83 relactation) Good book to read except the pages on "crying it out" pg189
Best of luck to you, I personally know how frustrating it is. I still cry that I didn't get it right for my first born.