In Battlefield 2 how do you upgrade your weapon if you chose to do it later?

when you are awarded a new weapon kit it asks you if you want to upgrade now or wait until later. i clicked later and now i cant figure out how to do it. unless i have to wait til i gain another rank which is way too long.In Battlefield 2 how do you upgrade your weapon if you chose to do it later?
Click BFHQ after you log in