You can throw in some alfalfa hay, that sometimes helps. The juice and water mixture helps sometimes. Just to clarify - the last litter died or just her mate? I just want to be sure on what you are saying. If the first litter died, that sometimes happens with first time moms, but it sounds as though this litter was premature and, to be honest, they may not make it either. It can be hard with the little teenies even if mom is a milking machine.
First I would get a working scale. They may surprise you and be larger than you thought. I would weigh them morning and evening to see if they are gaining. With kits that small, you don't have a lot of room to play with weight loss. If they are as small as you say, and they start to lose, then I would be sure to have the things for hand feeding on standby. You don't want to take over from mom, because then her milk will never come in, but you may need to supplement if they are losing.
If you haven't read it before, read the FAQ regarding kit care. It gives the recipes for a wet and dry formula, as well as technique for hand feeding.