oscommerce mods

We have a website almost fully complete. we however require changes before the site can go live. changes are listed below. it is a modified OSC website, so its not a plain vanilla installation. im available to chat online please send me msg. 1) our website keeps switching users / shopping baskets. when we test the website, when we log in, it keeps changing users. if i am logged as person a, and person b logs in, person b is logged in as person a. THIS MUST B FIXED. 2) shopping basket keeps changing numbers 3) if we have an attribute, and there is 1 value color = "red", if there is another attribute color = "blue" . then we only get red, NOT blue. we require ALL attributes. 4) need to change categories text to images 5) are there extra security patches you can ad? if so please outline the cost of this 6) we also need to run a chron and we do not hav a copy of chron. please give a cost for this 7) one of the addresses is not working. all other addresses are , except this one. 8) Time Frame? Thank you