Here is a pretty cookie-cutter and very strong raiding spec/glyphs:
Talent Calculator - World of Warcraft
The prot subtree can actually be a much stronger tool for healing than the extra crit provided by ret. Longer and Stronger Sacred Shields, coupled with a raid-wise cooldown you can use every two minutes. This spec actually has 3 floater points which, in this case, are placed in 2/5 Benediction and maxing 2/2 Imp LoH.
For HL it can be more efficient to use a single nightmare's tear to fulfill your meta, allowing your remaining gems to be all yellow. Alternatively if you are able to get 2 sockets bonuses, 1 Luminous Ametrine and 1 Dazzling Eye of Zul can be equally as effective. Obviously as you've stated you need to get all Brilliant King's Ambers.
You'll likely run into regen issues when starting out with HL, so in order to optimize these some of your enchants could be changed. First and foremost your helm arcanum and shoulder inscription should be changed to the SP/Mp5 alternatives. As well you should probably opt for 16 intellect to bracers and 30 intellect for your weapon.
You will likely want to swap your leg enchant to Sapphire Spellthread (SP/Stam). The spirit you are currently recieving from your Brilliant Spellthread is really wasted itemization and not doing anything for you. The stam gain is helpful for personal survivability and will yield a marginal increase to the effectiveness of your Hand of Sacrifice and Divine Sacrifice cooldowns.
The ideal itemization for HL is haste/mp5; after that haste/crit and then crit/mp5. Haste is definitely our best throughput stat so I would look for attaining quite a bit of that, while maintaining 'acceptable' amounts of regen. Hopefully after some time you will find what is a good amount of regen to support your particular playstyle.
Having said that I'm just going to list some attainable/farmable upgrades that are either crafted, from emblems, or from 5 mans.
Libram: Libram of Renewal (ilvl 200) Emblems of Heroism
Head: Headguard of Inner Warmth - Emblems of Triumph
Neck: Love's Prisoner - Bronjahm (H) FoS
Chest: Chestpiece of High Treason - Falric (H) HoR
Bracers: Sunforged Bracers OR Black Chitin Bracers - Crafted Plate/Mail
Shield: Protector of Frigid Souls - Scourgelord Tyrannus (N) PoS
Trinket*: Tears of the Vanquished - The Black Knight (N) ToC
*This is over the Ephemeral Snowflake
Obviously this list is very limited since I tried to restrict to non-raid upgrades.
Hope this helps!