Importing the data from Paradox using a direct method is not possible due to limitations of both applications and, instead, you will need to use a 3rd party driver which makes the communication possible. For this operation, you will need QODBC because it integrates into the Quickbooks application. From that point, Paradox should be able to communicate with Quickbooks for data exchanging.
A tutorial is available how to properly connect QODBC with Quickbooks.