Hi Rebecca,
Sounds like the PHP Memory on your server is being overused. This is different to hard drive space, and is something that you can request your host to increase for you. I checked your site and it seems you are using 44.4Mb out of your allowed 64Mb. I’d suggest you request this to be increased to 128Mb.
I attempted the upload process manually myself, however it seems that you can’t even access the Media Library (Media in the WordPress menu) – so I would definitely recommend you request this change with your host.
Hope that helps, let us know how you get on with that & re-attempting after. Increasing to 128Mb should relieve all those problems 🙂
Thanks,
– Ed