Well don't stop farming valor yet. The next patch (5.4.8) will allow you to upgrade your gear and weapons another 8 levels. See the blue post.

Recommended strategy: Just prior to the patch release, max out your valor at 3000. The day of the patch, use your valor to upgrade 6 of your best pieces (e.g., legendary cloak and warforged). Then head to the Timeless Isle and turn in 30,000 timeless coins for an additional 1000 valor. Now upgrade two more pieces of gear for a total of 8 upping your item level by about 4. Then show up for the raid and beat the heck out of Garrosh and anyone in his path.

Actually this patch may signal the end of the valor grind (if you have enough timeless coins). Method: At the beginning of the week, take one toon to the Timeless Isle and turn in 30,000 timeless coins for 10x Deeds of Valor. Use them to get 1,000 valor. All of your toons will now get Valor of the Ancients (50% valor buff). Take each of your other toons to the Timeless Isle and turn in 18,000 timeless coins for 6x Deeds of Valor. Use them and get 6*150 or 900 valor. Then run one heroic dungeon and you're done for the week!