Upgrading LG P500 (Optimus/Maximo One)
OK, to answer the part of your question that wasn't answered by the questions I linked in the comments: Yes, you can unofficially upgrade to 2.2 or 2.3.  This XDA thread has a relatively comprehensive list of ROMs.  It looks like all the 2.3 ROMs are pretty buggy, so you should probably go with a 2.2 ROM that looks good to you; after a brief look, the one I would probably try is called "AmberHome".  The thread for each particular ROM should have installation instructions.