Getting back into the work force

I have been a stay at home mom for some time.  I have only had 1 job outside my home that i held for 5 months, but had to leave due to work related injury and no longer able to do the job.  Noone at the work place cared.  I don't think i made a good impression there.  There was a lot of backbiting, belittling and underminding going on.  It was a entry level, base pay job as i had no work experience at that time. 

I've done hospic care for seniors in my area, who have all passed, so i have no references from any of them.  Many died unexpectedly.  I have also done volunteer work at my church and tried my hand at a home based business that didn't go really well.  I need to go back to work, but after putting a resume together and looking at it, i have loads of experience with home/housewife duties, but very little work experience.  I've gone to an interview and was stumped by the question what motivates you???  And didn't really understand some of the other questions, but tried to answer as honestly as possible.  Is there any help to good interviews and writing a resume that helps you sell yourself??? Can anyone suggest something for assisting me in putting all the experience down on paper in a good format???  I know what i need to bring in for a job, but i'm even unsure as to what the market is paying at this moment and the field i need to go into.  Also, is age a factor??? I'm 50 and feel like i'm starting all over again.  Plus i have limited mobility due to advanced arthritis in both knees.  Long distance walking is not a plus... so i'm looking for a position that i can sit at.  HELP!!!  ANY suggestions would be appreciated!