Mrsv: I would suggest that the biggest problem are the naps, and I think you would agree. I think that issue should be tackled, because without good naps, you won't have good night sleep. Have you tried pu/pd or sh/pat? Either way, in order to keep her happy, she needs to learn to nap longer.
Please don't consider what you pumped, exactly what your lo is getting. If you haven't pumped in a month, it's possible your breasts have forgotten what a pump is.... so it's very hard to tell what you are producing. I can only ever pump 2oz and my lo is 7.5 months old.
I think your lo is overtired from not napping and hten uses her nursing time to settel and sleep, so she's likely not getting the amt of milk she needs to keep going and it becomes a vicious circle.. (and one I think all mamas can relate to)
I understand about not getting outside in the cold. The other way to extend A time I found was to have someone else entertain her. But that wans't much of an option for me, but it may work for you.
Let me know if there is any other way we can help.
I hope this info is some help.
{{{hugs}}}