Yamilet financed her home purchased with Merced Credit Union with a fixed rate $30$ year mortgage at $7\mathrm{.}8\%.$ Yamilet took out a $$520,000$ mortgage that requires fixed monthly payments that include interest and part of the principal.

$($d$)$ What is the fixed monthly payment that Yamilet has to pay to Merced Credit Union? Round your answer to two decimal places. $[4$ Points$]$

$($e$)$ Suppose Yamilet has been making payments for $7\mathrm{.}5$ years. How much interest has she paid over the course of $7\mathrm{.}5$ years of payments? $($Hint: You'll need to calculate the total amount paid already and how much Yamilet has remaining on her loan after $7\mathrm{.}5$ years of payment$).[8$ Points$]$