OK, my most immediate concern is that I made three ~$500 bitcoin purchases this weekend and downloaded the Bitcoin-Qt client, but ran out of HDD space just before it finished synchronizing the BlockChain, and now I don't even know what my BTC balance is, if my value is lost, or what.
Now I don't know what to do.
I was at least bright enough to have made a screen print of the three bitcoin addresses from the client and also of my BitInstant orders (while they show the destination address and $ amounts paid/recieved, they don't list the amount of bitcoin I assume and hope that I received), but I can't find my private keys in the client, though it appears that I am able to Send Coins from the tab of that name.
I don't even know what my total amount of bitcoin is since Bitcoin-Qt hasn't finished synch-ing up, and I'm just sort of stuck without either bitcoin or fiat since my HDD is down to only ~200MB left with 1,746 blocks remaining.
What should I do?
I read that the Multibit and Electrum wallets seem to need less computer resources, so I was thinking/hoping that I could maybe transfer my bitcoin to one of those wallets, or maybe to the StrongCoin online wallet or other secure recommendation as an interim step, but I don't even know the precise quantity of bitcoin that I should have in my bitcoin addresses, or if I can even send them without knowing my private keys.