What is the rise and run? It still looks too steep. Covering choices will not help with that issue.

If the rise is over 8" that could be your problem.

Does it need to be attractive? http://www.uline.com/Product/Detail/S-9778/Anti-Slip-Tape/Anti-Slip-Treads-6-x-24?pricode=WY493&gadtype=pla&id=S-9778&gclid=CKKPl4K39M0CFdKIfgodUz0K6A&gclsrc=aw.ds

You should have grabbed the chance to make it code compliant, as any rebuild of stairs required. Coverings will make very little difference to something so fundamentally unsafe.

You could paint them and add an non-skid additive to it http://www.homedepot.com/p/BEHR-Premium-Non-Skid-Floor-Finish-Additive-97024/202301601

I live in a neighborhood full of 1920's houses, and many of them have attic and basement stairs similar to yours. Looks like you and your husband did a beautiful job with a difficult situation.

Are you thinking of staining or painting? You can use exterior paint designed for porches, stairs, etc. I'll bet you can find a stain with a finish that isn't slick. Talk to the folks at a good full-service paint store where pros buy their stuff. I would probably avoid carpet -- my neighbors used carpet on their basement steps and it make already narrow stairs even narrower.

One final thought -- a second handrail might be a good idea.

If you are going to try carpet runner, try it before you finish it, like that you could rip it out and patch and paint it. In my experience carpet is still slippery and even more so than the wood. There are various glue-on textured materials available for commercial use. They are not super attractive, but it might be your only way to make it safer. I agree the proportions are not right, that would have done most of the difference.