Creating a New Record Using the Most Recent One

I have two separate reports.  One report uses daily rates, the other has weekly rates.  My user would like to get the weekly rates into the report with daily rates.  By that I mean, if he enters a rate for an ID on 3/23 and looks at it on 3/27 before a new rate is entered, instead of it saying NULL or being blank, he wants to pull that rate on 3/23 as it's own record until the next time he enters a date.  Is this possible?  Running out of ideas.

For example, in this table he would like a daily record.  So from 3/23 until 4/13 he wants an entry every day of the rate from 3/23 (0.14)