Roses and Zantedeschia

what is best site to get standard roses im after a tri colour one as dont have much hope for one i currently have 

want it for middle of garden and maybe dotted in wee border like roses had good luck growing poundstretcher ones were just twigs now loads growth ready to go outside

also i got a couple zantedeschia tubers from poundstrecher do i just pot them up inside til i see decent growth then pop out in bigger pots, do they get big in their first year? do you plant them near surface like begonia tubers? thanks Sam