All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, it should be mentioned that you did really well by repenting to Allaah, treading the correct path, establishing the prayers and being keen on seeking knowledge.
We ask Allaah to make us all firm on His true path.
You should know that it is not permissible for a Muslim man to establish an affectionate relationship with a non-Mahram woman, and it is not permissible for him to talk with her except for a necessity and without being in seclusion with her, and provided he feels secure from being tempted by her.
Therefore, you have to avoid talking to this woman or keeping company with her in order to be safe in your religion.
As regards calling her to Islam, you can guide her to some Islamic websites in English. You can also inform her about some Islamic centers in her country.
But it is not permissible to marry her, as she is still a non-Muslim and has not yet embraced Islam wholeheartedly without any doubt.
Allaah says (what means): {And do not marry polytheistic women until they believe. And a believing slave woman is better than a polytheist, even though she might please you.} [Quran 2:221]
Being convinced by Islam and wishing to embrace it is not an sound reason for you to get married with her. However, if she embraces Islam, becomes steadfast on it, and abides by the Sharee'ah, then it becomes permissible for you, Allaah willing, to get married to her.
Allaah Knows best.