Well, first, i'll welcome you in our community, we are all happy to know our community growing(please forgice me my cruel english, i know it's terrible)
So, your Questions:
1. The "Gem-Bags" I'll copy some text of the Readme, most times it's a very good way to answer questions, here it is:
originally written in Readme
Description of Gem-Bags:
There are 7 Gem-Bags for each gem type.
The bag can contain 2 gems of same type and quality, if you put in a third of same type and quality it willbe converted to next better quality.
There can be 200 perfect gems in bag
Maximum is 200 Perfect, 2 Flawless, 2 Normal, 2 Flawed and 2 Chipped Gems of same type.
So 208 gems in bag for only 1 place in inventory, you save 207 places!
How to put gems into gem-bags
Put the gem-bag and the correct gem type into cube, press the button, thats it
If there are already 2 of same type in gem bag, you get a better one that you can cube again into stash, until its a perfect one
How to get gems back?
Put the gem-bag into the cube, press the button, and one of the lowest will be put off from bag
To get the perfect gem, you must remove up to 8 from other type...heee you got 207 saved places..so do a little work 
Where to get this gem-bags
Lysander (Act2) costs 750 Gold
Now your 2. question:
Well, you should be able to find good things by playing the game through, or to get good runes should be very easy, you can gamble them. You can also cube some equip, the recipes are in the Readme, but you have to know, you can't cube the "uber-items" but it's very possible to get thtough without them.
So to get a some good equip shoudn't be too hard, only what belongs your resists, this could become pretty tough, because on difficulty hell you will loose 250% of your resists and believe me, its hard without any good resists. But you can make runewords into magic and rare items, they could have some nice @ like a high number of enhanced defense and resists, so don't be afraid.
Your 3. question:
It should be possible to get over lv 9x in single-player by playing normaly through. If not, you just should train a little bit, its easy to know the monsters lv, just take a normal, magic or rare item dropped by a monster where you want to train. You see the itemlevel on the item. So you should know the Monsterlevel, because:
Itemlevel of a normal/magic/rare item=Monsterlevel
If the level of your char is more than 5 levels lower or higher than the monsterlevel, you won't get good eyperience. If your level is right, you should get good eyperience without great problems.
Last but not least, 4.
Yes it's true, most of us speack german, but there are also people from switzerland and other european countries here. But almost everybody understands english, most can write better than me^^
Here are some usable links:
I hope i was able to help you
mfG Lord-Bahamut
€dit: woah, i was the 1. who wrote the thrad and the last who answered...
