You can already add sockets to items at the gem vendor, Zanafer Stark. It's her 2nd tab.

Also, level 60 is just the level requirement cap for gear. Gear continues to get better affixes well into the 100's. My understanding of it is that the top tier of affixes are available at level 115, but the affix pool is watered down by lower-tier affixes at this level, For this reason, it's better to farm in even higher tiers, where the lower-tier affixes are no longer able to roll onto drops. I farm (Sarisels) at 163 because I've read that 160 is the last cutoff for lower-tier affixes. I do 163 instead of 160 just to be safe because it's unclear as to whether the drop-off is at 160 or after 160. I've also read a couple people saying 151 is all you need to farm and some others believe 187 nets the best chance at the top tier, though I suspect some BMing tin hatters might be involved there.

163 seems the most reasonable to me since 160 is the start of the Ascended page.
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Trulain