congrats on the house!!
what i do is mulch the root area with leaves - i do that in all my
flower beds. i put down a layer of leaves that's about 6 inches deep - i pack them down a bit too.
i got some of those white plastic coated wire edger things from the dollar store and i put them at the edge of the beds to hold the leaves in place (otherwise, they blow away).
you can either trim the bush back now, or wait until early
spring to do it. i usually wait until
spring to trim them back (sometime around st patty's day).
when you prune them back, you can go as low as 2 feet high - if it's a tall grower, it'll have no problem
growing next year even if you take it down that low!
you don't have to do such a severe cutting back tho - you can leave some of the canes a bit taller than that if you want.
next year, after the blooms fade and the petals start falling off, cut the bud off - that should stimulate the bush to produce more blooms.
the yellowing leaves are most probably due to the time of year...they could be an indication that the bush has black spot - it's a fungus that many
roses get. it's easily treatable with a spray - i use spectracide brand (was using the ortho stuff until they took it off the market). that's something you don't need to worry about at the moment tho...
a good, deep mulching is the best thing to do for right now.