、？
So what you're saying is I should use this vase as a urine bottle?
Literal
In-other-words, this vase [obj-を] urine-bottle [gen-の] substitute [as-に] use [quotative-って] thing [question-か]?
つまり to frame the summary, here of an implausible interpretation. の代わりに 'in place of / as a substitute for X' is a set adverbial. ってことか 'so you're saying that X?' (from というこ とか) packages the preceding clause as a quoted summary, turned into a sarcastic rhetorical question. 尿瓶 'urine bottle' is medical vocabulary for a bedside urinal.