I got front and rear HEL lines off eBay last year, about £45, not sure of the seller but Mr Brakelines rings a bell. Make sure they've got stainless bolts/ends and not Zinc plated. I fitted the "racing" setup to the front which is two lines straight out of the master cylinder, was cheaper than 1into2 through the splitter at the time and works just as well (also less chance of leaks).
Can't remember where I got the seals from, generics off eBay I think. If you go that route make sure you read the listings properly though, from memory there are plenty of sellers that are creative with their advertising and don't sell you a full set.
To rebuild the standard calipers you need the following seals:
Front; large dust x4, large fluid x4, small dust x4, small fluid x4 (x2 of each type of pot per caliper)
Back; dust x2, fluid x2
You also need quite a lot of patience when it comes to bleeding the new system