by "bike shoe" do you mean clipless pedals and shoes? If so, these will improve your riding straight away, as more of the power from your legs will be transferred to your pedals. Fitting clip-on tribars to a road bike is of limited value anyway for various reasons, plus you can't/shouldn't use tribars if you're training in a group. Get the pedals and shoes first.
whereas you can get tribars from about £30 upwards - possibly less on ebay.