you can try using a small syringe or plastic spoon to feed her.
it's difficult to force open baby's mouth wider, what i did previously was shape the breast then when dear son open his mouth, i will quickly then push the nipple plus aerola area into his mouth. sometimes not successful, so unlatch (push the last finger into dear son mouth and unlatch the nipple) and try again. that was super difficult. can take me almost 1 hr just to get dear son to drink for about 15 mins only.
otherwise, you may need a lataction consultant's help or drop by any polyclinic (ask for breastfeeding help, usually done by the nurses there, about less than $10 for the session. need to coincide with baby's feeding time for it to be effective) or breastfeeding friendly pds to ask for help