Welcome to the Wefugees Community and thank you for sharing your situation with us!
I am sorry to hear that your asylum application was rejected in Slovenia. However, as Slovenia (like most of the European countries) also applies the so-called "Dublin-regulation", you will probably not be able to re-apply for asylum in another country.
Still, every case is different and it is hardly possible to elaborate your situation and options based on few information.
In general, you cannot apply for a visa for a country in which you already stay, as a visa is kind of permission to enter a certain country (or region in the case of Schengen, i.e.). Visas are issued in embassies or consulates.
Do you think it will be possible for you to get in touch with legal advisors in Slovenia? I found this website which provides some contact details.
I hope you can find some useful support there and please feel free to get back to us with any further questions.
All the best,