MIL and money

Okay ladies I need advice on what to do. My husband and I owe his mom $850. She helped us out when we really needed it and I'm forever grateful. My husband and I had a rough year with finances and we're finally back on our feet so now we can pay his mom back. My husband wants to give her $100 a month until we pay her off completely. Apparently she wasn't happy with that amount and wants us to pay her more, but we can't because we have a new home to pay for and we have a baby. Then she suggested to give her the entire $850 when we get our taxes. I was all for it because I no longer want to deal with her because although she helped us she's not the easiest person to deal with. my husband wants to put the money we're getting from our taxes in a savings because we don't have any savings at all and we're only getting a little over $1000 back. I understand where he is coming from because we really had a rough year financially and he doesn't want us to go broke trying to pay his mom. I don't know what to do because she really wants it all at once, or more than $100 a month. We also still have other payments we need to make monthly so more than $100 would be very difficult. What would you ladies do, or how would you handle this? Would you give her more than $100 a month and go back to struggling? Would you give her basically all of the tax money and barley have any left over for a savings? Or would just pay her $100 a month and won't care if she's upset about that?