Fix and Improve Java Web Application

We have a Real Estate web application that is currently being used by one real estate agency and that was developed for us about 4 years ago using Java and MySQL. It has some issues that need to be fixed, and we also would like to improve it to make it more functional for the way we need to work today. Some of those improvements include making it compatible or adding integration with the social networks and some others are related to making it possible for the application to be used by different real estate agencies (that are part of a real estate association) in an independent but possibly cooperative fashion. The issues that need to be fixed are: 1) Make the Weblinks functionality work 2) Check why changing user passwords or adding new users sometimes makes it display a blank page when trying to log in 3) Make it handle prices better, since it sometimes makes blank pages appear on the website instead of the property lists it should display. We would like to add/improve the following: 1) The possibility to show pictures in the lists it shows on the website. It already shows pictures, but only in the property details. 2) The possibility for it to work with templates so the information it handles can be displayed using different layouts for different websites. 3) Imrove the way it handles photos. Currently this works fine and we can upload up to a maximum of 5 at a time, which is fine, but we would like to have the ability to order them dinamically, instead of adding a number to each one as we upload them, for instance. We also have some crazy ideas that we don't know if they are even possible, for instance about the possibility to dinamically create slide shows in the form of videos from the uploaded pictures. This we could discuss in more detail with the developer. 4) We want to know if it's possible to add the feature to log into the application using Gmail, Facebook or Twitter, like we've seen on many websites now, so that we're logged into both at the same time. 5) We want to add the feature for it to display a website compatible with mobile devices, especially iPhone and Blackberry. 6) We want to add integration with the social networks, especially YouTube, Facebook, Twitter and Google+ so that we can publish to those networks and possibly to a blog from within the control panel of our application. 7) We want to know if using Google Maps is a possibility so that we could integrate that functionality into the application. 8) We would also like to make it possible for it to use different databases for different users so that every "agent" or "agencies" could have their own private property portfolio while maintaining as well the capability to publish individual, specific properties to the general website, sometimes called a Multiple Listing Service or MLS, as well as sharing some specific details (but not all) of those properties with the other real estate agencies that are part of the association. 9) Possibly, depending on costs, we would like to develop an application for the iPhone/iPad and Blackberry or other smartphones based on the same web application. VERY IMPORTANTLY we will make the decision as to whom we choose to help us with this based not only on their ability to get this accomplished and how much they charge, but also based on the possibility to develop a working relationship with this person or team for them to maintain and continue to improve the application or applications in the future. Last, we have no idea how we can go about working with a developer on this and we think that getting a quote and possibly ideas as to how we can get this fixed and improved is probably the best way to do it. That's the reason why we are not going to specify what type of project this is or what budget for it we're considering. We can work on that, obviously, within whatever is reasonable and it could become a multi-step process.