Your most expensive problem is that a V-tec motor is designed to operate at higher RPM's than your motor can handle. This would mean that you'd have to get stronger pistons and connecting rods (or conrods as they're referred to). You'd also need to upgrade your valve springs to cope with the higher RPM and you might also have to get a new camshaft. All in all, you're probably going to be spending about $2000 just on that. This by itself won't actually make your car perform any better, but without these upgrades, your engine won't last.
Another problem with your particular car is that you have a single camshaft doing the work, but a V-tec will need to have a double-camshaft setup, meaning you'll need to have a new cylinder head, including camshafts installed.
I'll stop now. The short answer is that if you want V-tec, it's going to be cheaper to just buy a secondhand V-tec.