How do I set limits with my mother?

Hi my mom has lived with me and my husband for 20 years. She will be 81. I am not working at the time so Monday through Friday during the time my husband works its me and mom. While I set her typing this I realize I have her out of the house doing some type of running 4 out of the 5 days.It is getting groceries, bible study, getting her hair done.Or just letting her walk around a store to look. We take her out to dinner on Friday nights and to lunch after church on Sundays. On top of that. she is the biggest drama queen and everything that goes on is all about her,she has to be in the mix of everything.If someone makes her mae she tears them apart.I told my brother and he agrees she has issues. Not so much health as mental. She feels she needs to be catered to and noone should go anywhere without telling her or taking her.She does have curviture of the spine so she has trouble walking long ways or for long periods of time without a cane or something to hold onto.She will want to go to the mall then in 20 minutes is ready to leave.I takes 20 minutes to get there so it is fusterating to say the least. If we stay home she makes ne feel I should do nothing but sit in front of her and talk to her.To tell the truth it is hard to find anything to talk about .As she always wants to talk about the past how bad she had it how she lost her husband and two sons. No one has had this happen.She tells so many lies to other people and even us we never know when she is being turthfull.So this also makes it hard to talk to her.But yet on Saturdays if my husband and me want to do something with out her she trys her best to make us feel bad about it.I sometimes just plain resent her.She will not get involved with any activities that i will not do. It is getting the time of year that on the weekend we want to ride are bike or take the boat out. We have taken her to the boat but again she is ready to come home in a half hour and it takes longer to get to the lake than that.Plus our adult kids and grandkid like to ski. Which she cant take going fast because of her back.Thank you for letting me vent.