Work needed on existing Magento website

Good Morning, I have a few issues with my site that are beyond me, are you able to provide a quote to fix them? 1) MOST IMPORTANT - 1 in 15 (approx) sales there is no order created in Magento. Customer says they saw an error message but cant recall what it is, i cant replicate it. Logging in var/log is not working so i have no idea what is causing it! Only find out about purchase due to receipt of payment from Eway/PayPal. 2) Help Desk Ultimate installed but when i go to Help Desk > Quick Responses i get a 403 forbidden, all files have permissions set correctly. 3) Think the layout of my product pages could be better but the coding is too difficult for me, can you make some suggestions? Also need bigger checkout button. 4) Login/Logout link at bottom of page, when logged in does not always change link text to logout. 5) Need direct 'buy' button for images in categories 6) Would also consider a change of colour shades so not so bright when seen on a mac, maybe more professional colours, your thoughts? 7) Also want a 'sign up for newsletter' checkbox added to Kontact us form with customer answer that appears in helpdesk ticket and also ability for customer to enter department for ticket and can also enter birthday. Thanks