You should be able to continue levelling in heirloom gear until level 81 - the level restriction on the gear includes level 80, but once you reach level 81 they will stop providing their experience bonus but continue providing their level 80 stats.
Is it worth noting that none of these patterns are specifically 'healing' patterns - this is a trend that shows throughout the Cataclysm expansion in that frequently healers end up going for gear with Intellect and another stat that isn't Spirit on them.
The gear set that can be made by leatherworkers is called The Big Wave. This item set is mail gear with four random stats on each piece of gear;
- Agility or Intellect
- A combination of two secondary stats (ie: Crit, Hit, and in some cases Spirit)
To make the full set you will need the following materials;
- 80 x Deepsea Scale
- 53 x Savage Leather
- 5 x Heavy Savage Leather
- 5 x Eternium Thread
Personally though, I would recommend that due to how close we are to Mists of Pandaria's release, to go with whatever gear is currently cheapest on the auction house on your realm, regardless of whether it is PvE or PvP gear - whatever gear you use before level 85 is only going to get replaced as soon as you reach the level cap so approach gearing characters at this point in the expansion as an exercise in spending as little gold as possible.