Remove the dead, diseased, weakest and oldest canes at the base to encourage new growth. You want to shape the climber so sun can penetrate the plant. Leave three or four of the most vigorous canes, and if possible, train them to fan outward. Some climbers bloom only in spring, some are repeat climbers. Prune spring bloomers after they flower, repeat climbers while they are dormant.
Roses thrive in a well-draining soil that's high in organic matter.
You might boost the organics in your bed. Fertilize your rose. You might try fish emulsion. A dose of Epsom salt will help the rose absorb magnesium. Use a third cup two or three times a year.