you could get more help when the exact route and flight dates are mentioned regading other options on TK. TK flies to IAD twice daily - so the bottleneck seems to be your first leg where we don't know from where you are departing.
I don't understand why it is not possible to get you on an earlier flight on the day of departure so you don't miss the connection - or is the two stop connection the only alternative?

If you don't like the TK alternative, the best way would be to cancel the whole ticket and rebook a routing that better fits you.