I fail to grasp your problem?

You can simply book the flight to FRA on the LH website, expect to pay a substantial amount though (in USD).....Unfortunately being so late in booking you can forget finding a bargain on LH. That never happens when you try booking a week in advance.

Ans as someone based in Venezuela you surely must know how it works with paying in local currency vs airlines that like to be paid in USD. TAP or some other airline seems to be the cheapest options by far at this time so why stick with LH?