Asalaamoalaikum warahmatullahi wabarakatuhu,
Allaho Akbar, Allaho Akbar, Allaho Akbar!!!
Welcome to the Muslim Ummah and congratulations on becoming a Muslimah, SubhanAllah.
With regards to garments, I understand that you reside in the UK? Whereabouts my sister? I'd say that to cover one self when praying so long as you have something loose and long to cover your body and hair, Inshallah Tallah you should be ok for the time being.
If the above sites don't help you, Inshallah try and visit a loose cloth shop (I'm Asian so I tend to visit Pakistani or Indian shops that sell loose clothes in London), Inshallah make one of the loose cloths into a nice big gown that covers your entire body (minus the neck and head which you can Inshallah cover with a scarf).
Alternatively, Inshallah if you drop me a message I'll try and help you out as much as possible (Inshallah send you an abaya and scarf through the post to an address of your choice??).
Wasalaamoalaikum warahmatullahi wabarakatuhu.
Your Sister in Islam.