It is a classic Annuity Due saving plan. The general formula is 


    FV = ,    


where  FV is the future value of the account;  P is the deposit at the beginning of each payment period (quarter, in this case) ; 
r is the quarterly percentage yield presented as a decimal; n is the number of deposits (= the number of the quarter periods, in this case).


2.5 years = 10 quarters.


From this formula, you get for for the monthly payment 


    P = .     (1)


Under the given conditions, FV = $450,000;  r = 0.04/12;  n = 10.  So, according to the formula (1), you get for the monthly payment 


    P =  = $40967.39.


Answer.  The necessary quarterly deposit value is $40967.39.