Your formula is correct- almost- in that in properly checks for the
value in H3. The way your formula is written, when H3 is between 3 and
25, the result will be 100*H3 (this is the value returned when the
logical value is TRUE). When H3 is not between 3 and 25 the formula
returns 2500. So you just need to reverse your formula:
=IF(AND(H3=3,H3<=25),2500,100*H3)
.... assuming you want the FALSE value to return 100*H3.