you could call the vet and ask to borrow a heat pad.
whatever you use must be cleaned properly. any bedding needs to be germ free(ie new and washed on a hot wash)
are the pups trying to suckle, you may need to open the mouth to get them on.if you are squirting the colostrum it may go down to quick and cause major problems.
try one at a time,prise the mouth open and put it on her teat....see how you go.
did the vet check for cleft palates,he should have done. that would cause them not to latch on.....
no email arrived,you can use the pm above