Wordpress Website Help

Hi all. I have recently had a new website designed via a freelancer on PPH and have been very let down. As soon as payment was made, I stopped getting any response from him.

So i'm currently stuck with an unfinished site, despite my intention to go live at the beginning of July. I need the following areas addressing:

1. The site at presents runs very slowly. I'm not sure why this is (he mentioned something to do with the membership plugin) but I want to get this sorted out, even if it means changing the membership plugin to one that won't affect the speed of the site. Or if it's the hosting, i'll upgrade it. But at present i'm just not sure why.
2. Uploading of the new logo and banner to replace existing ones.
3. Addition of the Twitter feed which for some reason is no longer on it.
4. Connection of the links menu to the actual pages
5. I wanted for new members to be able to sign up and pay a one-off fee of £10 for the first month, then £25 per month after that but the designer said that wasn't possible. I know this is definitely possible with paypal, so I would ideally like this doing if possible (but this is less important than the other features)
6. Connection of social media links to my pages
7. The login box shows up all wonky on my computer. This may be a browser issue as I have a mac so it's safari that I use, but obviously macs are quite common these days so it really needs to work on all computers.
8. Finally, I would like the site transferred so that it shows up on the actual website name rather than /site/

I would appreciate quotes on this but please bear in mind that I have already had to pay for the web design so my funds are relatively limited. As I said to the last designer though this was just the foundations of the site, there are other things I want to add going forward so I am looking for someone to work with.