Thank you for including a photo and don't worry I am confident I can promise you a better rose garden. First it looks like your rose has black spot on the leaves. Just pull them all off as new growth will appear this spring. Try not to wet the foliage when you water and give your plant good air circulation to prevent black spot.  Next any rose growing in a container is going to need extra fertilizer. I use Osmocote on all my roses in April and then again in June. Third, roses have deep roots and if you must grow them in containers I suggest a larger pot at least 24 inches deep. Use a good potting soil like Miracle Grow potting soil and make sure there is good drainage. If you can't make all these improvements right away then just pull off the infected leaves and fertilize now. You should be having a rosier future ahead. Keep growing, Marianne Binetti