Hi Rob,
to NGA
My thoughts:
Re-pot it into something larger. My daughter grows dwarf citrus in pots; I think her smallest pots are 15 gallons. Use a potting medium that drains quickly. There are some specially formulated for citrus and if you read the packaging, its the same formula as is used for cactus and palms.
Remember to water in the wintertime.
Meyer Lemons are hardy to about 20 degrees. If you put it out too early, the new growth will freeze back and you may lose the whole tree.
