I'd say at approx 4lb a week, your weight loss is excellent with what you're already doing, its easy enough to be talking about 'add protein' and 'cut sugar' but the facts are you enjoy that start to your day, it doesnt cause you to want more food half an hour later, it isn't hampering you at all to keep it just as you enjoy it.
and i'd be wary of changing it for something you'll enjoy less, it might make you look for treats elsewhere in your day. I also have a pleasant breakfast i know i could make it healthier but there's no value in taking out every pleasure, only the ones we cannot control.
you didn't mention how much cereal you are having.. are you somewhere near the right serving size or at least at a known calorific quantity for your breakfast?
I love those frosted wheats too.. they're great mixed half and half with honey-nut shreddies btw... yum yum... i'm like you, i can cope with a fun breakfast and still eat healthily the rest of the day.. so enjoy it. you're doing just fine (in my opinion)
Its only the ones who are losing weight by uncomfortable methods that have to worry how fast they are losing it (ie. before they give up).. we can also lose weight enjoyably and then it doesnt matter so much exactly how fast we lose it, as we can be quite happy to keep enjoying our healthy weightloss routines (with healthy little treats) until we get there.
the main thing is to keep it enjoyable, comfortable, relaxing, annnnnd healthy.