I don't really get what your saying.. but it might help to put tape where the notes go if you don't already have that.. like this:
http://ecx.images-amazon.com/images/I/215APHWHHQL._AA160_.jpg
I'd try to get a few lessons if you can also to help you if you don't already have a teacher.
A low two would be something like second finger C on the A string. C# on the other hand, would be a high two. A low c (or anything "low" using the 2nd finger) should be easier than a high note because your 2nd finger should be placed right next to your first finger, given that your first finger is not on a Ab (G string), Bb (A string) or F natural that isn't a problem.
In the A scale, IMO, its harder because your hand is in a slightly abnormal position because of the C# on G string (high three) although that makes putting 4th finger D (although you probably use open D) down easy because its right next to C#.
Do you know the difference between hole and half steps on violin?? Half steps should always be pretty easy (except not necessarily when there is a string crossing) because you put the two fingers right up close to each other. An example of a half step would be from C# to D (best on the A string) or from B to C on the A string. A whole step would be C to D on the A string (the C would be a low two) or A to B on the G string. Just remember its kind of different with the E string because F natural is back in "half position" so from F to G would be a whole step.
Hope that helped some.. Also remember that with the G scale it would be a high two in the D string (F#) and a low 2 on the A string (c) so your finger has to move from being right next to first finger to being next to third finger which is D. (That is in a two octave scale though. If you just doing one octave, you just need to worry about the high 2 on the D string for F#, then G right next to that, a half step away.
Really its just all about half and wholes steps in scales.
<Added>I just wanted to add, that on the finger tapes, the tapes go where the first finger would go (not any flats or F natural on E), then where a high two would be, then a normal third finger. You can check the third finger note (granted its not a sharp) with the open string below it :) So for example on the D string going up by the tapes would be first finger E, 2nd finger F# (high) and third finger G (check with open D for tuning if you want.. VERY useful skill especially when you get into different position stuff..)
If you want something else explained better or have other questions (hopefully that answered your question :)) feel free to ask!!
<Added>sorry I was going to add this before but I got distracted.
What your refering to with the low 2 is NOT a position, its just a low two. An example of second position would be when you have first finger on say C on the A string. In third position, your first finger would be where D is on the A string. Then E would be second finger instead of fourth or open, third finger would be F or F# and fourth finger would be G. You probably wont need to worry about these for a while!! Just when you need to go high than fourth finger B on the E string.
