I suspect you had no chance to gain sound Islamic education, in the absence of which our minds become more like a sponge absorbing all of the negative propaganda and images from the media and elsewhere. I pray to Allah to guide us all unto the straight path.

I am not in a position to answer all of your questions in detail in this limited forum. However, I would try to provide brief answers:

1. The Qur’an presents itself as the divine revelation; and challenges people to prove otherwise. In fact, if we consider the sheer number of eminent people from diverse backgrounds embracing Islam, and ask why they do so, the only viable answer is: they are astounded by the unique and inimitable nature of the Qur’an. You can verify this by studying the stories of those who have embraced Islam; and by reading the introduction to the Qur’an translations by scholars such as Marmaduke Pictktall, Muhammad Asad, and even the Orientalist Arberry and others.
2. The verse or verses of the Quran you are referring are to be explained by reference to the context, as such, they cannot be taken out of context to be applicable as if they are the universal principles of the Qur’an. I would urge you to read the work The Moral World of the Qur’an by M.A. Draz – a work based on a doctoral dissertation he submitted to Sorbonne University by an eminent scholar from al-Azhar. It shows that the verses such as the ones you cited are exceptions, whereas the verses teaching peace and non-violence are general. In other words, Allah tells Muslims in no uncertain terms that they are not to attack anyone who does not attack them: Here are two verses which clearly state this: “Fight in the way of Allah those who fight you and do not initiate aggression for God loves not the aggressors” (Qur’an: 2: 190)’ and “if they let you be and do not wage war against you and hold off their hands from attacking you, and extend peace towards you, then God does not sanction you to wage war against them.” (Qur’an: 4:90).
3. Now coming to the issue of sexual relations with those our rights hands possess, it is specific to the context of the condition prevailing before Islam as slavery was rampant all over the world; Islam form the very beginning set out to abolish slavery as can be seen from a careful perusal of the verses of the Qur’an. Unlike previous scriptures, there is not a single verse in the Qur’an going out and taking slaves in war or peace. Rather all of the verses there are about freeing slaves. Therefore, it is clear that the goal of Islam was to abolish slavery altogether.

Before its final abolition, however, Islam instituted practices best treatment of existing slaves, eventually liberating them.  Therefore, we cannot consider it as valid today.

You may do well to compare the Quranic teachings on slavery with verses in the Old Testament if you are interested in finding out the progressive nature of Qur’anic revelation.

In conclusion, I would also urge you to read the Preaching of Islam by Thomas Arnold in which he documents that Islam in so far it spread did so not through the use of sword; rather through peaceful preaching and beautiful examples.