How do I order a replacement key for my laptop keyboard?

My 2-yr old has discovered that the Ctrl key (lower left), springs and all, on my Dell Latitude D510 is quite easily removed. So much so that I don't know where the removable pieces of it are. Anyway, my service code has expired and I imagine that any online/offline support option will likely cost more than the replacement part. So far, I cannot locate "keys" on the accessories pages so I'm hoping that someone here can be of assistance? Anyone know how/where to pick one up for cheap? or not? Thanks--LITEbrte System Info: (why would it really matter in this case? :)) Dell Latitude D510 Windows XP Intel(R) Pentium(R) M processor 1.86GHz cpu 1 Gb of memory