So I transferred over the coins to another wallet, and then I used the dumpprivkey command in debug of BitcoinCore to get my private key. The only problem now is almost every Private key that I try to sweep into Coinimi wallet comes back with the message " the private key does not contain any funds". I've had more or less the same amount of BTC in my wallet since Mt.Gox exchange flopped, but all Coinimi could sweep out was a .1 BCH. How is that?
Two possibility here:
1- you are using wrong addresses, which didn't contained funds at the time. Try to search for more addresses. Try change addresses also (change internal/external to 1 instead of 0, you will get more addresses to scan with coinomi)
2- you didn't contained any funds at the time.