Joomla 1.5 to WordPress Conversion

I have a legacy Joomla 1.5.26 website. We need to convert this to WordPress. Along with the template (maybe brush it up a bit) and all the content and general style. There are 12,000 articles. Key plugins we use are simple image gallery and mavik thumbs. We expect all these images and articles to be transferred and working well. On WordPress I will need some posting/friendly options for our team as well as SEO, security, and someone maybe spending an hour or two per month to update it. You will notice the site also has lots of banners that appear dependent on the page. This will need to be possible. I would like to get someone to do this soon and launch the new updated version before the end of the year. This is a one month project. Here are some more notes on things we would need (some of this is obvious) Google Analytics Plugin Some sort of internal WP stats stuff, so we can see clicks on articles/stats. Easy Photo gallery plugin / simple gallery transfer (so all those articles still work with images) DISQUS commenting Easy template for articles for our other authors so they don't have to mess too much with formatting.. imagine some articles will get more than 1 photo and some zero photos. Some sort of versioning for authors too? Confirm old articles with photos (mavikthumbs) will transfer nicely? Auto post FB/Twitter plugins Right now we do not have author names, but I'd like to use them for new stuff.. is this possible without having to add them or display them for old articles? Or provide drop down menu with pre-set selections we can modify. Banner stats reporting. Right now Joomla gives me impressions/clicks for each banner I give to client. Banner randomness. You will see now all banner positions are shared, but some rotate on the live site. Ie.. page loads and you see 3 banners over 15 seconds in area (see top left) SQL optimization? With 12,000 articles we get a lot of burst traffic that puts a load on our database. We also have SEF urls, all sorts of page and JS/font compression... assume you will handle this Form page for email signups and advertising inquiries. Potential to significantly re-flow the front page news later on... not sure I like the list thing, but we will keep the same idea for now. Any warranty? Would also like you to monitor the site a few times when we get traffic loads on the new site, i.e. we will do an eblast to 10k people and get a ton of traffic. We can coordinate that.