From what I've gathered bitcoind is a command line bitcoin client. Is it bundled with bitcoin Qt, or do I have to download it seperately? If it's bundled, where would I go about finding and starting it on mac OSX?
While you can configure Bitcoin-qt on OS/X to run as a server, bitcoind gives you a method to make the API calls from the command line.
If you had a bitcoind, then these would be the steps:
Step 0.) of course,,, ... make a backup of your wallet.dat files (even the new one before you have any transactions).
1.) Configure bitcoin.conf with rpcuser=, rpcpassword= and server= so that you can access the API from command line bitcoind.
2.) Run bitcoind (or Bitcoin-qt with -server )
3.)
$ ~/bin/bitcoind -rpcuser=myuser -rpcpassword=mypassword listaccounts
for each of those accounts, do a getaddressesbyaccount. For example, for the default account (""):
$ ~/bin/bitcoind -rpcuser=myuser -rpcpassword=mypassword getaddressesbyaccount ""
Then get the private key (dumpprivkey ) for each of those addresses. e.g., for 1PC9aZC4hNX2rmmrt7uHTfYAS3hRbph4UN do:
./bitcoind -rpcuser=myuser -rpcpassword=mypassword dumpprivkey 1PC9aZC4hNX2rmmrt7uHTfYAS3hRbph4UN
4.) Then with the new, empty wallet, do the same steps 1-3. then importprivkey for each.
Now this can be automated with a script if needed. Also if you have wallet encryption enabled, you'll need to issue the RPC command walletpassphrase to make it so subsequent commands are accepted /
5.) Remove or replace bitcoin.conf so that you aren't leaving RPC enabled if you weren't previously using it.
This is not something non-technical people are expected to need to do. You may wish to contract with someone (reputable) recover these funds. From an export of the addresses it can be determined how much in unspent funds you have in that wallet. As far as a possible explanation of how this scenario you are in could happen, see issue #1428:
-
https://github.com/bitcoin/bitcoin/issues/1428
Good Luck 
