Good for you, for sticking it out and having this attitude, despite how hard all of this is! And congrats on your son.
No, it's is not too late. Absolutely not. If your son is premature, then any little bit you can pump for him makes a difference. Some moms just don't respond well to the pump--I'm one--but that has no bearing on how well you'll do when he can nurse. I wasn't getting much more than you are but I was eventually able to successfully EBF my twins. Even if you were to stop getting milk at all, you should still pump several times a day to remind your body that you aren't done. I have heard from multiple LCs that your body can easily relactate for an entire year after weaning, so a few weeks is nothing.
As for him being in there for 5-7 more weeks, mine weren't physically able to nurse until after that, so that also doesn't mean it won't work.
As for the supplement, it sounds like the Motherlove may not be helping much. Have you tried Fenugreek capsules? 3 of them, 3 times a day. The LCs I saw all said that regimen has given the best results in studies.
The other big thing that helps with milk production is skin to skin time. Are you able to hold him in the NICU? Can you take his shirt off when you do? I used to wear button up shirts to visit, because then you can just put the baby in the kangaroo position on your chest and sit there for a long time while he sleeps on you. Wonderful for milk! Also wonderful for your hormones, bonding, and mental health. If you haven't been doing this yet or aren't sure how to get it set up, talk to the doctor about it. There is a lot of evidence showing the importance of kangaroo care, so a neonatologist would be glad to help you make it work. Best of luck!