I've tried coinbase but it takes too long for the fund to available, 2 weeks and even more if you keep depositing the money.
Is there a reason why a two week delay is a concern? I wouldn't have thought it to be that relevant. Just transfer the money in and wait until you're comfortable with the price before buying. No point rushing to buy, just transfer the funds in as and when you have them. That would be my plan of action anyway.