I am facing a different hill. it goes up and levels off and it is in the front of my house. I used to have it landscaped with low spreading junipers until one year most of them up and died.
I have kept errosion to a minimum by using landscape fabric and mulch until I had the money to fix it up right.
Mine is in partial shade to afternoon sun....I have replaced the wood border with landscape wall bricks, This year I am sort of terracing it with field stone and will be planting a mixture of summer bulbs, perrenials and in the fall I will plant spring flowering bulbs. Along the bottom edge I will be using a ground cover called sedum...any low growing, ground cover would do but I got 12 plants on sale.
Since your sounds very shady I would try shade loving perrennials, maybe the use of garden fabric will help deter weeds and of course as generous use of mulch will help too. since there was so much back there and so many weed seeds to boot I would try not to turn the ground up too much and add top soil if needed. You know all the planting does not have to be done this year....I did a barron area about 10 years ago that looks just great now....it took a few years but it was worth the wait. Also look in your established landscaping for plants that need to be divided and use the "baby" plants to help fill in, in a year or two you will never know the diff.
Good Luck!
His will be done!