it says upload speeds next to the download speeds, or its sometimes in the small print, but dont be fooled, marketing takes over here, one of the Blueyonder packages there stated 384Kbps, thats not actually that good, by my calculations thats around 48 to 49 Kb/s which isnt that much higher than you state you have now. Be warned that unless you get crazy expensive thats about all your gonna get on a commercial DSL line, unless you fork out for cable or fibre then you might be a bit stuck.
Try contacting IS's manually (i.e. the telephone, yes its that plastic block thing with peoples voices inside of it, just in case you get lost in a digital world, dont email cos they never reply...) usually they will create custom packages for a bit extra a month, you should investigate how much it actually is to get say a 100Kb/s up speed. Prices are usually high because of the down speed, people get baffled by big numbers, so if you say your not too worried about down speed, you want up-speed more, then it might bring the cost down a bit.
hope this helps, i too am stuck on 45Kb/s up-speed, and i maintain 5 web sites constantly, takes a while sometimes.....
dragon