I have put together a number of variations for your request.Please note that the I used Gardiner Fonts and Transliteration Font for this post. The text in the brackets refer to Gardiner's sign list. As Asenath has so kindly posted, hieroglyphs are arranged in balanced groups or blocks in the best way that fills the space. The ":" between signs signifies signs that sit vertical to one another within their 'block'. The "," between signs signifies signs that sit horizonal to one another within their block. The a "*" followed by ( ) means that that the group of signs within the parenthesis sit vertical to one another yet horizontal to the sign that preceds the "*". Confused yet?..ha.

Let's first start with your name.Although a very nice name, it is not true Ancient Egyptian name and would have been spelled out phonetically with hieroglyphs. There are at least 4 different ways this can be done in the vertical orientation that you requested.
1. Ria = Rya= ¨ êê º = [D21:M17,M17:D36]
The glyph for "r" or the "open mouth" would be first, underneath would be the "i,y" symbol or the "double reed leaves" and the "a" glyph or "arm with open palm" would sit below. All would be sized and positioned as if in an imaginary rectangular box.

2. Ria = Rya= ¨ ï º = [D21:Z4:D36].
The second glyph (two unknown strokes) also has the phonetic value of "i or y". Again, these signs would sit the same way as example #1.

3. Ria = Rya= ¨ êêU = [D21:M17,M17:G1]
Another sound that can be likened to the "a" sound in english is reprented by one of the "vulture" glyphs. It would take the place and positoning of the "arm with open palm".

4. Ria = Rya= ¨ ï U = [D21:Z4:G1]
Here you see both alternative glyphs used for "i,y" and "a".

Any one of these can be used, there may even be more. Choose which ever you like.

I know you asked for "Ria, given life, like Ra, forever, beloved of Isis", however, I do beleive an epithet such as "beloved of Isis" would come directly after your name and not "given life..."( Sankh wouldn't you agree??)

So in following tradition, "beloved of Isis" could be written in a number of ways as well. Because there are at least a half dozen ways "Isis" ca be written, I will only use one very common way. "Beloved of" can be written in at least two ways:
1. Beloved of = mry.t= Q êê Û = [U6, M17, M17:X1]
The first three signs here, "the plow (mer)" and the "double reed leaves (i,y) would sit side by side, directly under and at the same width as your name. The "t" glyph or "bread loaf" signifies that you are of femine gender and would sit centered under the above signs.

2. Beloved of = mry.t= K Û = [N36:X1]
Here the 'canal' sign alone has a phonetic value of "meri" in this context. It would sit directly below and at the same width as your name. Again the "t" or "bread loaf" would sit under it.

For "Isis" I would use the common form of this name:
Isis = Ic.t , Ac.t = ´ Û ¹ = [Q1*(X1:H8)]
Here the 'throne (As)' sign would sit followed by the "t (bread cake)" and "egg". The "bread cake" would sit above the "egg". Both wouls sit next to the throne sign and their combined height would equal the height of the "throne" sign.The "egg" here serves only as a determinitve meaning "motherly(?)" and has no phonetic value.

I will agree with Sankahare about the next set of glyphs for "given life, like Re, forever" ( di anx Ra mi D.t ).

I hope this was more of a help to you and less of a confusion!!