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.
If the credit card is Islamicly not permissible because it contains a usurious condition, then you should take the initiative to repent from this. The conditions of repentance if the sin is not against a human being (i.e. the sin is between you and Allaah) are as follows: to sincerely repent to Allaah, to regret having done the sin, to stop committing the sin, and to be determined not to return to it again. Whoever repents, Allaah accepts his repentance, and whoever repents is like the person who has never committed a sin. For more benefit, please refer to Fataawa 87903 and 86527.
Indeed, you did well by feeling regretful about the sin that you committed, because regretting the sin is one of the conditions of repentance, but it is also a condition to stop doing the sin, so you are obliged to stop dealing with the credit card.
As regards the car loan, if it is a usurious loan – as it appears from the question – then you are obliged to repent from that. Whoever repents from borrowing money with Riba is obliged to return the borrowed money and if he is able not to pay the interests, then he should not pay them. If there is benefit of not paying the interests by hastening to pay back the loan with Riba, then you are obliged to take the initiative to do so as much as possible. However, if there is no such benefit, then there is no need to hasten to pay back. The sin of borrowing with Riba falls on the person who borrowed the money, and he is permitted to use whatever he bought with the loan with Riba in any manner; for more benefit, please refer to Fataawa 93774 and 83935.
With regard to buying the bonds, if you mean the prize- bonds, then they are not permissible even with the intention of paying back the debts. Prize-bonds are not permissible because the person who buys such bonds takes the same ruling as a debtor, and every loan which involves benefit is Riba. Similarly, whoever buys the bonds in order to obtain the prize has committed gambling which is clearly forbidden, as Allaah Says (what means): {O you who have believed, indeed, intoxicants, gambling, [sacrificing on] stone alters [to other than Allaah], and divining arrows are but defilement from the work of Satan, so avoid it that you may be successful.}[Quran 5:90]
For more benefit, please refer to Fataawa 92525 and 84114.
Therefore, buying such bonds with the intention of paying back the debts that resulted from these forbidden transactions is not permissible.
Finally, we ask Allaah to enable you to sincerely repent and make what is lawful enough for you, as opposed to what is unlawful.
Allaah Knows best.