there are a number of child seats that will fit your car, unfortunately your are going to struggle in the group 0 catagory. (0-9months)
what you are getting confused on is a rear word facing child seat is from birth to 9 months (up to 20lbs) and after 9 months the child must face forwards (and use a child or booster seat until 147cm or 12 years whatever comes first)
I used to be the child seat trainer at halfords in lincoln (where i was the deputy manager)
the safest seat on the market at the moment that will fit group 1 (9 months to 4 years providing the child is over 20lbs in weight) is the Maxi-cosi Priori XP. this is an excellent seat with many features that are not available on any other seat on the market, such as the seat belt tension lever, 3rd hand assistance with the harnesses and the contoured base.
the seat is usually between £99.99 and £149.99 (but most halfords sales have them at £119.99)
halfords child seat experts are second to none and will never sell you a seat that is unsuitable, ask for their competency certificate before they attempt to fit the seat to your car.
again unfortunately because of the size of the micra, the front of the child seat, (where their legs are) is going to be fairly cramped up against the back of the seat in front. there really isn't anything you can do about this other than change cars..
i hope i helped.
