Hi lovemay and welcome to OB.
I know how hard it can be to have in-laws caring for your child, my MIL looks after our daughter for a few hours a day (mostly while she's asleep) and there have been quite a few times, especially early on, when I had to put my foot down and tell her not to do or say certain things. It's hard because it does feel disrespectful speaking to my MIL in that way but at the end of the day my daughter is much more important and if my MIL is doing something that I think is wrong or even detrimental to my daughter then I have to speak up. There are other things that still annoy me but I don't mention them because it's not worth rocking the boat and involves my house rather than my child IYKWIM.
I agree with Weegee about trying to find some extra space in your budget by cutting out any extras. It's amazing the things that we have that we think we can't live without but there are plenty of others that happily get by on a lot less so I'm sure I'm guilty of living with a lot of extravagences.
You could also contact places like barnadoes or church/cultural groups to see if they run daycares or maybe if you have any friends that are stay at home parents ask if they would help out for a small payment.